My AP Biology Thoughts

My AP Biology Thoughts  Unit 8 Ecology EPISODE TITLE: Conservation of BeesWelcome to My AP Biology Thoughts podcast, my name is Alex, here with Raelynn and Samiyah and we are your hosts for today's episode, coming from Unit 8 - our Ecology unit. Today we will be discussing bee conservation. Why are bees important to the environment?According to the US Department of Agriculture: “One out of every three bites of food in the United States depends on honey bees and other pollinators. Honey bees pollinate $15 billion worth of crops each year, including more than 130 fruits and vegetables. Managed honey bees are important to American agriculture because they pollinate a wide variety of crops, contributing to food diversity, security and profitability.” Pollinators - support plant populations Food crops as well as wild plants Why are bee populations declining? “Declines in bumble bee species in the past 60 years are well documented in Europe, where they are driven primarily by habitat loss and declines in floral abundance and diversity resulting from agricultural intensification.” (According to researchers from the University of Stirling) loss of habitats because of farming + urbanization Habitat fragmentation can impact surviving populations through genetic isolation (which causes inbreeding and makes population less genetically diverse, making them more susceptible to diseases) University of London (an issue of Apidologie): habitat loss is the “most universal and high impact factor driving bee declines.” https://www.ehn.org/monoculture-farming-is-not-good-for-the-bees-study-2639154525.html (https://www.ehn.org/monoculture-farming-is-not-good-for-the-bees-study-2639154525.html)  https://abcnews.go.com/International/monoculture-farming-modern-day-agriculture-killing-bees-scientists/story?id=80536659 (https://abcnews.go.com/International/monoculture-farming-modern-day-agriculture-killing-bees-scientists/story?id=80536659)  Climate Change University of London (an issue of Apidologie): Change in temperature and weather patterns due to climate change can significantly impact bee populations Additionally, loss of habitat due to rising sea levels can also cause negative impacts  https://www.businessinsider.com/insects-dying-off-sign-of-6th-mass-extinction-2019-2 (stats) https://www.eurekalert.org/news-releases/612063 (University of Maryland): October 2018 - April 2019: 40% of honey bee colonies in US died Many other insect populations in decline, evidence of a possible 6th mass extinction (“https://www.businessinsider.com/biological-annihilation-sixth-mass-extinction-2017-7 (biological annihilation)”) Pesticide use massively impacting bee populations and reproductive rates 44% fewer offspring in bee populations affected by pesticides in both youth and adulthood, according to scientists at the University of California These pesticides (neonicotinoids), while banned in many wealthier countries, are still used in and exported to low and middle income countries Varroa mite Colony Collapse Disorder  Bee conservation attempts:https://www.greatoldbroads.org/wp-content/uploads/formidable/44/Winfree-2010.pdf (Researcher) Winfree from Rutgers University Formal protection of threatened species - according to data an approximated 95,000 insects in general are in risk of extinction, however only 771 have been evaluated for candidacy on the global Red List. No bee species is listed under the US Endangered Species Act, even though many species are known to be rare and declining at a steep rate. An important step for the conservation of bees requires them to be identified as organisms that require protection The National Resources Conservation Service, an agency that operates under the United States' Department of Agriculture, has begun working with “agricultural producers to combat future declines by helping them to implement conservation practices that provide forage for honey...

My AP Biology Thoughts  Unit 8 Ecology EPISODE TITLE: Chimps in Uganda Welcome to My AP Biology Thoughts podcast, my name is kyle along with my handsome cohosts Shrithik, saahtih and gabe and we are your hosts for this episode , Unit 8 Ecology-Chimps in Uganda. Today we will be discussing Chimps and how they relate to the AP Biology Curriculum.  Segment 1: Overview of CHIMPS  Chimps in Uganda 98% share dna with humans  They move around and live in communities of individuals similar to humans Don't travel in groups like gorillas or other monkeys Around 1500 chimps in uganda live in 13 different communities inside the khabale forest with 5000 total in the country  Type 1 survivorship rate  K-selected species  Segment 2: Evidence that supports CHIMPS“You can also track chimps in Kyambura Gorge, Kalinzu Forest, Budongo Forest and in the Semliki Valley. Most of our Uganda holidays focus on Kibale, which has a very high success rate for sightings, and the atmospheric Kyambura Gorge in Queen Elizabeth National Park, where sightings are less certain but the scenery is spectacular.”  People have the hobby of following the chimps  Watching these communities shows the similarities of our survivorship and how they are K selected - K selected mean long term babies taking care of infants   Type 1 species  Population growth (exponential vs logarithmic) Natural limiting factors of population - Habitat loss, leopards How human activity affects chimp population - Hunting for bushmeat, pet trade and poaching and deforestation Segment 3: Connection to the Course These chimps relate to topic 8.3, population ecology in the AP biology curriculum. The chimps provide an example of organisms changing in order to respond to their environment as they have opposable thumbs like humans in order to help grasp and climb trees which indirectly helps them obtain energy The fact that the chimps have large group sizes, small body sizes and dietary flexibility increases their adaptive capacity to contribute to the success of their population in their habitat. The chimps eat figs, fruits, nuts, insects and even bark Thank you for listening to this episode of My AP Biology Thoughts. And another thanks to our sources, lonely plant.com, responsible travel, and worldwildlife.com.  For more student-ran podcasts and digital content, make sure that you visit http://www.hvspn.com (www.hvspn.com). And that's all folks and remember keep yo pimps close keep your chimps closer. Music Credits:"Ice Flow" Kevin MacLeod (incompetech.com) Licensed under Creative Commons: By Attribution 4.0 License http://creativecommons.org/licenses/by/4.0/ Subscribe to our Podcasthttps://podcasts.apple.com/us/podcast/my-ap-biology-thoughts/id1549942575 (Apple Podcasts) https://open.spotify.com/show/1nH8Ft9c9f6dmo75V9imCk (Spotify) https://podcasts.google.com/search/my%20ap%20biology%20thoughts (Google Podcasts )   https://www.youtube.com/channel/UC07e_nBHLyc_nyvjF6z-DVg (YouTube)   Connect with us on Social MediaTwitterhttps://twitter.com/thehvspn ( @thehvspn)

My AP Biology Thoughts  Unit 8 Ecology EPISODE TITLE: Marine Life on the Catalina CoastWelcome to My AP Biology Thoughts podcast, our names are Sofia, Addie, Gillie, and Diana, and we are your hosts for the episode called Unit 8 Ecology- Marine Life on the Catalina Coast. Today we will be discussing Marine Life on the Beautiful Catalina Coast and how it relates to the AP Biology Curriculum. We want to thank our sources for the information presented in this podcast episode today which you can find the citations and links to these sources in the show notes. Segment 1: Overview of Catalina CoastHave you ever heard of the film Step Brothers? Perhaps… the Catalina Wine Mixer? While this is a great film in movie history, it does not correctly portray the true biodiversity of the Catalina Coast. Now that you're speaking about it, I remember looking up the Catalina Coast a while back and getting really intrigued by all of the stuff I was finding. I went down a rabbit hole for like three hours. I didn't even know there was that much to look at. I might have to plan a vacation there. I'm not going to lie I tend to stay away from the water because to quote Raven “I can't swim”  And not to mention all the animals…. The ocean is a mystery that I do not wanna explore But nonetheless, here we are today learning about the insane vastness of biodiversity The Catalina Coast is located 23 miles off the coast of Southern California. If you're taking a helicopter, you can get to the Catalina islands in 15 minutes. It is a part of the Channel Islands archipelago and is one of the four southern channel islands Segment 2: Evidence that supports Marine Life on the Catalina Coast Catalina Coast is the home of the Blue Cavern Onshore State Marine Conservation Area If I remember correctly, Katy Perry says, “nothing comes close to the (I'm sure) Blue Cavern Onshore State Marine Conservation Coast”, and that includes humans, as it is a conservation For the record, Sofia is not remembering this line correctly, but the idea is there. More than 60 endemic species… meaning they are only found in the Catalina Coast region Conservationists are working to preserve these endemic species to maintain the genetic diversity of this region Ensuring that each species can adapt to environmental factors Since Sofia wanted to quote Katy Perry, I'll quote a super underground artist that you guys definitely wouldn't know…. They're called the Four Preps…… They sang a song called 26 miles (Santa Catalina) So anyway, they talk about how it's only 26 miles from Cali baby and it's full of romance. There are several types of species on Catalina Island. This includes different types of seals, such as the Phoca vitulina, or the harbor seal. The island also includes different types of snakes, lizards, frogs, and more.  My favorite sea animal is the sea lion. Does the Catalina Coast have those too? Of course they do! The California Seal Lion, or the Zalophus Californianus, are one of the many species included in the Catalina Coast's environment. Segment 3: Connection to the Course 8.6 biodiversity The biological variety and variability of life in a given ecosystem Since the Catalina Coast is home to so many species, it indicates that there is a lot of biodiversities The high level of biodiversity makes it so that the organisms can better respond to changes in their environment Thank you for listening to this episode of My AP Biology Thoughts. For more student-ran podcasts and digital content, make sure that you visit http://www.hvspn.com (www.hvspn.com). Cheers to the Catalina Coast!!!!!  Music Credits:"Ice Flow" Kevin MacLeod (incompetech.com) Licensed under Creative Commons: By Attribution 4.0 License http://creativecommons.org/licenses/by/4.0/ Subscribe to our Podcasthttps://podcasts.apple.com/us/podcast/my-ap-biology-thoughts/id1549942575 (Apple Podcasts)...

My AP Biology Thoughts  Unit 8 Ecology EPISODE TITLE: The Isle of WolvesWelcome to My AP Biology Thoughts podcast, our names are Olivia, Anushka, Mea, and Hana and we are your hosts for the Unit 8 Ecology-the Isle Royale Study podcast. Today we will be discussing the Isle Royale Study and how it relates to the AP Biology Curriculum.  Segment 1: Overview of the Isle Royale StudyCamping —> DOCTAH guise —-> isle royale —-> us listening to him talk :) Segment 2: Evidence that supports the Isle Royale StudyWinter controls the ticks (kills them all if cold temperature)  Provide ex of trophic cascading  Predator prey talk abt it Human interaction/interference (trails, being on/off)  Coloring of the wolves  Talk abt winter study (break island into quadrants and take populations #'s)  Segment 3: Connection to the CoursePredator-prey relationship:   Trophic structure: a flow of energy between organisms in an ecosystem  Energy flow  Parasitic  Importance of genetic diversity Thank you for listening to this episode of My AP Biology Thoughts. For more student-ran podcasts and digital content, make sure that you visit http://www.hvspn.com (www.hvspn.com).  Music Credits:"Ice Flow" Kevin MacLeod (incompetech.com) Licensed under Creative Commons: By Attribution 4.0 License http://creativecommons.org/licenses/by/4.0/ Subscribe to our Podcasthttps://podcasts.apple.com/us/podcast/my-ap-biology-thoughts/id1549942575 (Apple Podcasts) https://open.spotify.com/show/1nH8Ft9c9f6dmo75V9imCk (Spotify) https://podcasts.google.com/search/my%20ap%20biology%20thoughts (Google Podcasts )   https://www.youtube.com/channel/UC07e_nBHLyc_nyvjF6z-DVg (YouTube)  Connect with us on Social MediaTwitterhttps://twitter.com/thehvspn ( @thehvspn)

My AP Biology Thoughts  Unit 8 Ecology EPISODE TITLE: Pacific Garbage Patch and Its Impacts on WildlifeWelcome to My AP Biology Thoughts podcast, my name is Angelina and my name is Emily and we are your hosts for the Unit 8 Ecology podcast on the Great Pacific Garbage Patch and Its Impacts on Wildlife. Today we will be discussing the Garbage Patch's harmful effects on aquatic life and how it relates to the AP Biology Curriculum.  https://www.nationalgeographic.org/encyclopedia/great-pacific-garbage-patch/ (https://www.nationalgeographic.org/encyclopedia/great-pacific-garbage-patch/)  Segment 1: Overview of Pacific Garbage Patch and Its Impacts on WildlifeBackground info:  The patch is a vortex of plastic waste and debris which is very calm and stable but surrounded by four currents that sweep debris into the center  Two distinct collections of debris, the Western and Eastern Garbage Patches  Pacific: Garbage is spun and linked together by the North Pacific Subtropical Convergence Zone, where warm water ( South ) meets cool water ( Arctic ) Much of the debris is not biodegradable and has taken a significant toll on the aquatic wildlife  Most of the debris is plastic, which is not biodegradable but rather breaks down into microplastic particles Segment 2: Evidence that supports how the Patch Harms Wildlifehttps://theoceancleanup.com/great-pacific-garbage-patch/ (https://theoceancleanup.com/great-pacific-garbage-patch/)  According to National Geographic, oceanographers and ecologists discovered that about 70% of marine debris sinks to the ocean floor, so the patch may also be an underwater heap of trash  Marine debris is known to be harmful to wildlife  Ex: Loggerhead sea turtles often mistake plastic bags for jellyfish  Ex: Albatrosses mistake plastic pellets for eggs and feed them to their chicks, which then die of starvation or ruptured organs  Ex: Seals and other animals get entangled in abandoned nets and other waste  hear about turtles a lot because of many companies movements to stop using straws, but we dont always hear about the other species being affected so it is definitely important to learn about these organisms as well BIG ONE: Marine debris can disturb marine food webs As microplastics collect near the ocean's surface, they block sunlight which prevents plankton and algae to grow  Many organisms depend on these producers for food Since they are at the foundational levels of the food web, when they are negatively impacted, the whole web is as well  Segment 3: Connection to the CourseEnergy flow: Affects all wildlife (trophic structure) Kills species, leaving less energy in ecosystem If organisms consume garbage, the organisms feeding on them will be indirectly feeding on garbage Bioaccumulation Impacts humans as well We should all do little things to help the environment Thank you for listening to this episode of My AP Biology Thoughts. For more student-ran podcasts and digital content, make sure that you visit http://www.hvspn.com (www.hvspn.com).  Music Credits:"Ice Flow" Kevin MacLeod (incompetech.com) Licensed under Creative Commons: By Attribution 4.0 License http://creativecommons.org/licenses/by/4.0/ Subscribe to our Podcasthttps://podcasts.apple.com/us/podcast/my-ap-biology-thoughts/id1549942575 (Apple Podcasts) https://open.spotify.com/show/1nH8Ft9c9f6dmo75V9imCk (Spotify) https://podcasts.google.com/search/my%20ap%20biology%20thoughts (Google Podcasts )   https://www.youtube.com/channel/UC07e_nBHLyc_nyvjF6z-DVg (YouTube)   Connect with us on Social MediaTwitterhttps://twitter.com/thehvspn ( @thehvspn)

My AP Biology Thoughts  Unit 8 Ecology EPISODE TITLE: South African Rhino PoachingWelcome to My AP Biology Thoughts podcast, my name is Keenan Wallace and I am your host for this episode called Unit 8 Ecology-Threatened Rhinos in South Africa. Today we will be discussing South African Rhino Poaching and how it relates to the AP Biology Curriculum.  Segment 1: Overview of Rhino Poaching numbers poached rising in recent years: 13 Rhinos poached in 2007, peaked in 2015  1175 Rhinos killed in south africa in 2015 (more than 3 a day),  number poached has since declined with 394 killed in 2020 Rhino population has decreased from 1 million in the 1800s to only 27,000 in the wild today. Rhinos are a keystone species: They play an integral role in their ecosystem and many other species in the ecosystem depend on their presence Segment 2: Evidence that supports dangers of rhino poaching Rhinos are so large that they actually Geo-form: change the land around them Rhinos often wallow in mud to keep cool and ward off insects.  This helps maintain waterholes When the rhinos get out they track the fertile, nutrient rich soil that accumulates in waterholes far and wide, distributing the nutrients.  Rhino dung supports other species and food chains Rhino dung fertilizes soil Dung beetles lay their eggs in rhino dung, which also supports species that eat the beetle larvae A number of bird species rely on Rhino dung for insects and seeds.  Rhinos support fly and tick species as well as animals that eat them, like terrapins (a kind of turtle) and oxpeckers (the iconic symbiotic relationship) Keep grass short, allowing plant species that can't survive among long grass to thrive. Segment 3: Connection to the Course Without rhinos, all of these roles would be left unfilled and with its foundation gone the ecosystems would begin to collapse. (keystone species) When you hear about rhino conservation, this is why it matters.  Thank you for listening to this episode of My AP Biology Thoughts. For more student-ran podcasts and digital content, make sure that you visit http://www.hvspn.com (www.hvspn.com).  Music Credits:"Ice Flow" Kevin MacLeod (incompetech.com) Licensed under Creative Commons: By Attribution 4.0 License http://creativecommons.org/licenses/by/4.0/ Subscribe to our Podcasthttps://podcasts.apple.com/us/podcast/my-ap-biology-thoughts/id1549942575 (Apple Podcasts) https://open.spotify.com/show/1nH8Ft9c9f6dmo75V9imCk (Spotify) https://podcasts.google.com/search/my%20ap%20biology%20thoughts (Google Podcasts )   https://www.youtube.com/channel/UC07e_nBHLyc_nyvjF6z-DVg (YouTube)  Connect with us on Social MediaTwitterhttps://twitter.com/thehvspn ( @thehvspn) Sources: “Vanishing Rhinos - The Impact of Rhino Poaching on the South African Ecosystem. (n.d.). The Scientista Foundation.” The Scientista Foundation, http://www.scientistafoundation.com/lifestyle-blog/-vanishing-rhinos-the-impact-of-rhino-poaching-on-the-south-african-ecosystem. Accessed 1 Dec. 2021. “Poaching Numbers | Conservation | Save the Rhino International.” Save The Rhino, https://www.facebook.com/savetherhinointernational/, https://www.savetherhino.org/rhino-info/poaching-stats/. Accessed 1 Dec. 2021. “Why Are Rhinos Important for Ecosystems? - Africa Geographic.” Africa Geographic, https://www.facebook.com/Africa.Geographic, 25 May 2020, https://africageographic.com/stories/why-are-rhinos-important-for-ecosystems/.

My AP Biology Thoughts  Unit 8 Ecology EPISODE TITLE: Birds of Paradise Mating RitualsWelcome to My AP Biology Thoughts podcast, my name is Xavier and I am with Celine and Sofie and we are your hosts for Unit 8 Ecology-Birds of Paradise Mating Rituals. Today we will be discussing Birds of Paradise Mating Rituals and how it relates to the AP Biology Curriculum.  We want to thank our sources for the information presented in this podcast episode today which include National geographic and BBC Earth. You can find the citations and links to these sources in the show notes. Segment 1: Overview of Bird  The birds of paradise are some of the most fascinating birds in the world, from their wide range of behaviors and striking coloration of the males, I would love to ask you some specific questions about them. I have looked over many different species and their behavior, but I am particularly interested in the elaborate mating displays performed by male birds of paradise. Of course, let me begin with a bit of background on the species. Birds of paradise are members of the family Paradisaeidae (Para-dice-see-a-die), which researchers think evolved on the island of New Guinea. The family is comprised of 43 species, most found on the island of New Guinea. Two species are found only in the Moluccan Islands to the west of New Guinea, and four others are found mainly in northeastern Australia. The family of birds includes astrapias, manucodes, paradisaeas, parotias, riflebirds, and sicklebills. Segment 2: Evidence that supports Animal Behavior within the Birds of ParadiseI know many species of birds are sexually dimorphic but what does this mean for the bird-of-paradise  Yes, this means the males and females have different appearances. So the males have elaborate feather patterns that they use in their mating displays while the females of these species have a more dull and camouflaged appearance  So while the females are watching the Males perform these displays what is their key concern when choosing which male to mate with?  The female choice appears to be based on the vigor of the males' display meaning their physical strength and health. Which can be seen in the condition and color of his feathers.  So the female chooses a vigorous mate, ensuring that her offspring will also be relatively healthy.  Exactly, the strongest, most brightly-feathered males have a better chance of attracting the females, while less attractive males may be overlooked.  I was most interested in a species of male Superb bird-of-paradise with their dark black cape feathers and almost like a “psychedelic smiley face.” The way he snaps his tail rhythmically slowly, flashing a breastplate of iridescent like feathers. I'm sure the female's prefer their beautiful feathers. Like I had mentioned it really depends on what the female wants to pass on to her children. This is their key concern when mating. Impressive as it is, the male's beauty is impractical. Excessively long tail feathers might be great for attracting mates, but they aren't exactly useful for survival. In fact, it's easy to see how they might be a hindrance.  So how did these features evolve seen as the males need them for mating but doesn't survival play a role? Well, when resources are plentiful and there are few predators, females don't need the males to defend them, provide food, or help raise young. They can be picky when it comes to choosing a mate which leaves the males to work hard to impress the females. This is why sexual selection is so relevant in the bird-of-paradise Segment 3: Connection to the CourseNow you may be thinking to yourself, how does this relate to the AP Bio Curriculum Well...the birds of paradise mating ritual is a great example of courtship behavior  This is a behavior that results in reproduction, and in this case specifically through the visual and auditory stimuli that birds...

My AP Biology Thoughts  Unit 8 Ecology EPISODE TITLE: Disappearance of Costa Rican Leatherback Sea TurtlesWelcome to My AP Biology Thoughts podcast, my name is Beth Hooks, Emilie Sawicki, and Nick Bailey, and we are your hosts for episode # called Unit 8 Ecology-Costa Rican Leatherback Sea Turtles. Today we will be discussing the disappearance of Costa Rican Leatherback Sea Turtles and how it relates to the AP Biology Curriculum.  Segment 1: Overview of Costa Rican Leatherback Sea Turtles Disappearing  Leatherback sea turtles are one of the most ancient reptiles, as well as the most endangered sea turtles. Their habitat spans from the North Atlantic to the south pacific. Their lifespan is estimated to be 50 years or more. They feed on open ocean prey such as jellyfish and salps (NOAA.org).  Their nesting beaches are generally located in tropical latitudes, especially in Trinidad and Tobaago, the West-Indies, Gabon, Costa Rica, and on the Pacific coast of Mexico (NOAA.org). The greatest threats worldwide are incidental capture in fishing gear, hunting of turtles, and collection of eggs for human consumption. Climate change, loss and degradation of nesting and foraging habitat, ocean pollution, and vessel strikes also pose a threat to the population (NOAA.org). The Leatherback Sea Turtles are listed as endangered under the Endangered Species Act (NOAA.org).  Segment 2: Evidence that supports Costa Rican Leatherback Sea Turtles Disappearing The turtles have had a 40% mortality rate in the returning adult population over the last 8 years. This data was obtained by fitting turtles with satellite transmitters and following their migration. Many disappear, and it is believed that mostly because they get stuck in fishing lines (World Turtle Trust).  Projects that monitor nesting sites conduct nightly census work and fit nesting turtles with Passive Integrated Transponders. Projects that protect nests from poachers attempt to maximize the number of hatchlings that survive (World Turtle Trust).  Segment 3: Connection to the Course The jellyfish population is increasing due to rising global temperatures. This suggests that energy sources are not the problem. The population curve of a predator generally follows the population curve of their prey, so if the jellyfish population increases, this means that the turtle population should increase. However, since so much ocean pollution is present in the form of plastic bags and turtles often mistake them for jellyfish, the jellyfish population may be increasing due to less predation (Lamb, 2017).  Climate change has caused new predators to migrate to places where sea turtles are. This has begun to cause a trophic cascade in some environments that affects the phosphorus content of the sea grass (BurkHolder, Heithaus, Fourqurean, Wirsing, Dill, 2013).  Additionally, the migration of these turtles is an innate behavior. An innate behavior is a behavior that's genetically hardwired in an organism and can be performed in response to a cue without prior experience At this point, the leatherback turtles have great opportunity to increase as a population, but due to density independent factors, which are unrelated to the size of the population, their population is unable to increase and move towards their carrying capacity. Some examples include human interference, climate change, and natural disasters. So, as the population continues to decrease, these factors will continue to be detrimental towards the population and the sea turtles will have a greater risk of becoming extinct.  And finally, the disappearance of the Costa Rican Leatherback Sea Turtles is just another reminder of the detrimental impact that humans have on the earth and the environments on it. Our footprint is impacting so many ecosystems, environments, and species, and causing many of them to become endangered and even extinct. 

My AP Biology Thoughts  Unit 7 Natural Selection EPISODE TITLE: One Skink, Five Skink, Egg Skink, Live SkinkWelcome to My AP Biology Thoughts podcast, my name is Diana along with Sofia and Saahith and we are your hosts for Unit 7: Examples of Evolution-The Three Toed Skink- and I know what you're thinking…. nope this is not derogatory or a slur. In episode 117, we will be discussing the species the Three Toed Skink and how it relates to the AP Biology Curriculum. We want to thank our sources for the information presented in this podcast episode today which include Reptiles Magazine, National Geographic, Eurekalert.org, syfi.com, phys.org, and sciencedaily.com. You can find the citations and links to these sources in the show notes. Segment 1: Overview of The Three Toed Skink (Diana)The three toed skink, aka Saiphos equalis, is found in eastern Australia, primarily in New South Wales and Queensland. The three-toed skink is sometimes mistaken for a snake, eats crawling insects and worms, and is active at night. The three toed skink is a “bimodally reproductive species” WHATS THAT this means that some lay eggs and some give birth. Dr. Whittington, from the School of Life and Environmental Sciences and Sydney School of Veterinary Science at the University of Sydney in the article “Biologists observe a three-toed skink lay eggs and give birth to a baby,” says, “Put in the context of evolutionary biology, being able to switch between laying eggs and giving live birth could allow animals to hedge their bets according to environmental conditions." There are at least 150 evolutionary transitions from egg-laying to live-bearing in vertebrates. To elaborate on this, Sofia will share the interesting evidence of evolution of the Three Toed Skink. Segment 2: Evidence that supports The Three Toed Skink (Sofia)Thank you, Diana, for that beautiful introduction to our beloved skinks. In the article, “Which Came First, the Lizard or the Egg”, Dr. Camilla Whittington from the University of Sydney skink research team describes how the earliest vertebrates were egg-layers, but that over thousands of years, embryos remained inside their mother's for longer, until some began live births. WHAAAAATTTT?? The Three-toed skinks are an example of a species that have evolved to perform both reproduction methods of egg-laying and live births. Get yourself a skink who does both. Direct observation studies have revealed that the skink species located on the warm weathered coasts of New South Wales lay eggs rather than performing live birth. On the contrary, the skinks located in the cold weathered mountains of South Wales give live births. Scientists suggest that mothers in warm climates lay eggs to conserve their own bodies' resources, while mothers in cold climates protect their young by keeping them inside the oven for longer. Additionally, evolutionary records show that nearly 100 reptile lineages have independently made the transition from egg-laying to live birth in the past, which supports that these skinks transition to adapt to their environment. On to Saahith my HANDSOME best buddy, who has some very wonderful connections between the three-toed sinks and our lovely evolution principles.  Segment 3: Connection to the Course (Saahith)These skinks relate to topic 7.2,natural selection , 7.6 evidence of evolution, and 7.7 common ancestry in the AP Biology Curriculum. In the course, it is taught that evolution is supported by scientific evidence from many disciplines (geographical, geological, physical, biochemical, and mathematical data) the Three toed skink is an example of geographical evidence as skinks in warmer areas lay eggs and skinks in colder areas give birth to live younger. The warmer areas lay eggs in order to conserve body resources and live longer and produce more offspring. The colder areas give birth to live young because they want them to stay inside the adult in order to grow more and stay in a warm environment

My AP Biology Thoughts  Unit 7 Natural Selection EPISODE TITLE: Natural Selection of the Tomcod against PollutantsWelcome to My AP Biology Thoughts podcast, our names are Celine, Xavier, and Sofie and we are your hosts for this episode called Unit 7 Natural Selection: Examples of Evolution-Toxic River Fish. In episode 120, we will be discussing the Toxic River Fish and how it relates to the AP Biology Curriculum.  We want to thank our sources for the information presented in this podcast episode today which include national geographic and NPR. You can find the citations and links to these sources in the show notes. Segment 1: Overview of Toxic River Fish To begin with the overview, the species of fish we will be discussing today are the tomcod This species of fish lives in the waters of New Jersey and New York, usually found in the Hudson River where pollutants and chemicals such as polychlorinated biphenyl was dumped between 1947-1976 by General Electric companies Therefore they developed a gene the resulted in an immunity Segment 2: Evidence that supports Evolution Toxic River FishWe can see the evolution of Toxic River fish from the molecular Evolution that was changing in DNA sequences.  When the pollutants entered the hudson river it resulted in 95% of the fish developing liver tumors. The toxins from the electric company entered the nucleus of cells and For some fish it caused a distortion of DNA instructions. This would cause some to most of the fish in the river to get sick and die. By chance, the Toxic River Fish had a version of that gene that tolerated the PCB and toxins The toxic river fish evolved to handle dangerous chemicals that were dumped in the river and Overtime the toxic river fish that had the resistant gene did better than the fish without it Technically they're not mutants, but the chemicals did give one genetic group an advantage over the others This is where survival of the fittest played a role, the fish that could resist toxins would have a higher rate of survival than those without out resistance  The ability to resist the toxins caused the toxic river fish to lose some ability to cope with natural stressors like low oxygen or abnormally high temperatures but they still had advantage above other fish Segment 3: Connection to the CurriculumBiology is the study of biotic organisms, and focuses on the dynamic and behavior. Evolution is 1/12 characteristics of biology. It connects to the course because it distinctly shows evolution through natural selection Natural Selection: is the process to which an individual is selected to survive because of different phenotypes. We can see that the toxic river fish fit to survive in the polluted ecosystems, as they adapted to the environment because of their specific phenotype.  Thank you for listening to this episode of My AP Biology Thoughts. For more student-ran podcasts and digital content, make sure that you visit http://www.hvspn.com (www.hvspn.com).  Joyce, C. (2011, February 17). Toxic Avengers: Pollution Drove Fish Evolution. NPR.  https://www.npr.org/2011/02/17/133842089/toxic-avengers-pollution-drove-fish-evolution Minard, A. (2011, February 19). Hudson River Fish Evolve Toxic PCB Immunity. National Geographic.  https://www.nationalgeographic.com/science/article/110217-hudson-river-pcb-fish-evolution-water Music Credits:"Ice Flow" Kevin MacLeod (incompetech.com) Licensed under Creative Commons: By Attribution 4.0 License http://creativecommons.org/licenses/by/4.0/ Subscribe to our Podcasthttps://podcasts.apple.com/us/podcast/my-ap-biology-thoughts/id1549942575 (Apple Podcasts) https://open.spotify.com/show/1nH8Ft9c9f6dmo75V9imCk (Spotify) https://podcasts.google.com/search/my%20ap%20biology%20thoughts (Google Podcasts )   https://www.youtube.com/channel/UC07e_nBHLyc_nyvjF6z-DVg (YouTube)   Connect with us on Social Media...

My AP Biology Thoughts  Unit 7 Natural Selection EPISODE TITLE: Butterflies and ParasitesAnushka Agarwal, Olivia Lundquist, & Hana Hamid  Welcome to My AP Biology Thoughts podcast, our names are Anushka, Olivia, and Hana and we are your hosts for Unit 7: Examples of Evolution-Butterflies and parasites. In episode 114, we will be discussing Butterflies and parasites and how they relate to the AP Biology Curriculum.  Segment 1: Overview of Butterflies and Parasites  To start off, what is evolution? Evolution is the process by which different organisms develop from their ancestors to adapt to the environment they are living in. This idea was proposed by Charles Darwin to explain how species have the ability to evolve. We can look at the Blue Moon butterflies for examples and how they adapted to their environment to protect themselves from the killing parasite. The Blue Moon Butterfly, or Hypolimnas bolina, is an eggfly commonly found in New Zealand, Australia, New Guinea, Solomons, etc. The blue moon butterfly's mating season is normally in the spring and summer. Their name is derived from the 2 bright circular patches on the backs of the males. Natural selection occurring between the butterflies and parasites is an example of evolution happening in real time. This is because scientists discovered that the bluemoon butterflies developed resistance in a span of 10 generations (which lasted a year).  Additionally, the peppered moth is a species of a night-flying moth which is most commonly found in the northern hemisphere in countries such as Europe, Asia, and North America. They are generally small moths (only 1.5-2.5 inches) and their eggs normally hatch during mid summer. While some moths are typically light in color, many have dark skins and normally have extra camouflage to protect them from their predators (which includes ​​flycatchers, nuthatches, and European robin). We can see a difference in the colors of the peppered moth due to the Industrial Revolution marked an era of industrial change in Europe and the United States from 1760-1840, which affected not only economy but the environment as well.  Segment 2: Evidence that supports Evolution of Butterflies and Parasites  mutation the changing of a structure of a gene that may result in a variant form → can have impact bc it has the potential of getting passed down that leads to evolution mutation: males can survive the infection of parasite that kills male embryos normally they cant(mutation allowed for them to live and complete term/live) Natural selection (blue moon butterflies)  Since the parasites normally targeted male blue moon butterflies, their population was a staggering 1%. However, because these butterflies obtained immunity from the parasite, their population bounced back to 40% in less than a year!  natural selection the process of adaptation of a species in order to survive. It is caused by environmental factors.  before industrial revolution: moths were white 2% were black after industrial revolution: moths were black 5% were white not eaten as frequently after revolution when dark bc they blended better with the environment  artificial bc the environment changed, causing the need to adapt, bc of humans and factories How peppered moths can be considered natural selection before industrial revolution: moths were white 2% were black after industrial revolution: moths were black 5% were white How did this happen( factories were being built during the industrial revolution and burning coal for fuel helped them run, resulting in a dark smoke to cover the area Moths pass their color to the next generation ( a mutation in the DNA of a single moth caused the mutation to pass on to other moths) Dark moths started to live in dark forests (aided them in camouflage from predators)  Segment 3: Connection to the Course AP Biology has a strong focus on...

My AP Biology Thoughts  Unit 7 Natural Selection EPISODE TITLE: Unit 7: Darwin's FinchesWelcome to My AP Biology Thoughts podcast, my name is Shrithik Sekar, Kyle Mason, Gabe Moriello, and I am your host for Unit 7: Examples of Evolution, Darwin's Finches. In episode 116, we will be discussing this topic and how it relates to the AP Biology Curriculum.  “We want to also thank our sources for the information presented in this podcast episode today which include (Britannica, Galapogosisland.org, and Crash course Biology on Youtube). You can find the citations and links to these sources in the show notes.” Segment 1: Overview of Darwin's finches  What are Darwin's finches?  Who is darwin? - Geologist and Biologist, who formed the theory of natural selection. Known for his contributions to Science of evolution. He studied many finches which were found in the galapagos islands located 1,000 km off the coast of Ecuador  What were the finches? - These finches were a Group of 18 different species found in the Galapagos island. Darwin found the finches were all closely related with small direct observations that he made during his time in the Galapagos islands  What did he study? -During his studies while in the Galapagos islands, he concluded the speciation of the finches which is known as the experiment of Darwin's finches   How does it relate to evolution? - It relates to evolution because it is an example of Direct observation  Segment 2: Evidence that supports Darwin's finches  Connection direct observation evolution  What is direct observation of evolution? - Through observation, in small population sizes, it can be found many changes of one species to then create many subspecies. Through direct observation of evidence in almost every species. THis idea had to do with the last universal ancestor, how all species are alike in many ways and all stemmed from the same ancestor. These finches dna is super similar, but these small differences of dna created a difference in appearance which was found ny darwin.  ( This begs the question of ) Why are the finches an example of evolution? All 18 species of Darwin's Finches were originally one finch species on the coast of south america. However, Darwin discovered that this species branched off into 18 different species on the Galapagos islands depending on the finches' environment  What Key pieces of evidence did darwin find? - Darwin found the difference, fruit eating finches had wide beaks, insect eating finches had narrow beaks, and based on different factors of each finches environment each species had a different characteristic change. - GO TO Image  Segment 3: Connection to the CourseThe 5 pieces of evidence - of evolution.  How do these ideas of evolution connect to our Biology class?   ( Relates to AP bio curriculum 7.2 - Natural Selection)  ( 7.4 - Population Genetics  (7.6 - Evidence of evolution  (7.7 - Common Ancestry  Direct observation is only one example of evolutionary evidence  5 other examples - Fossils, Geological evidence, Change in DNA, Homologous structures  All apart of either natural or physiological selection  Natural selection is a part of the 5 fingers of evolution ( Sexual Selection, Genetic Drift, Gene flow, Mutation)  Darwin's finches show that adaptive evolution among the finch populations - the finches evolved different beak types depending on which food they ate, showing how natural selection is a factor in pushing populations to evolve Thank you for listening to this episode of My AP Biology Thoughts. For more student-ran podcasts and digital content, make sure that you visit http://www.hvspn.com (www.hvspn.com). Ceeeyaaa!!!!!! Music Credits: "Ice Flow" Kevin MacLeod (incompetech.com) Licensed under Creative Commons: By Attribution 4.0 License...

My AP Biology Thoughts  Unit 7 Natural Selection EPISODE TITLE: The Threespine SticklebackWelcome to My AP Biology Thoughts podcast, our names are Beth, Gillie, and Addie and we are your hosts for Unit 7: Examples of Evolution- The Threespine Stickleback. In episode 119, we will be discussing The Threespine Stickleback and how it relates to the AP Biology Curriculum.  Segment 1: Overview of Threespine SticklebackThe Threespine stickleback fish live in the ocean and in lakes. The fish who live in the lake have been separated from the ocean sticklebacks for thousands of generations. Although there is a difference between ocean and lake sticklebacks, all freshwater sticklebacks can vary in shape and size depending on habitat. Scientists looked into the differences between lake and ocean sticklebacks by taking 50 fish from each population and comparing them. Segment 2: Evidence that supports Threespine SticklebackFreshwater sticklebacks and ocean sticklebacks have a number of different physical characteristics. For example, Ocean Sticklebacks are generally much larger. They also differ in body length, spine length (and number), fin shapes, number of lateral plates (​​Genetic Science Learning Center, 2017, August). The scientists observed that the average number of lateral plates for ocean sticklebacks was 33. On the other hand, the average number of lateral plates was 5 in the lake stickleback. Additionally, Michael Bell ran an experiment where he determined just how fast this evolution was occurring. He tracked the genes of stickleback fish in lakes in Alaska and determined the speed at which evolution occurred (in just a decade) (Robert Sanders, M. R., & Sanders, R., 2021, June 21). More interesting, however, is the fact that fish evolved convergently across the globe due to similar conditions, despite being isolated for decades (Shen, H., 2012, April 04).  Segment 3: Connection to the CourseThe Threespine Stickleback demonstrates natural selection and adaptation in the environment, which directly relates to section 7.1 and 7.2. The data of how lake and ocean sticklebacks have adapted over time is a prime example of fitness. The environment of the lake and the ocean are different, and as a result, the lake stickleback has evolved to better suit this body of water. The evolution of the Threespine Sticklebacks caused by natural selection in different environments connects to 7.1 and 7.2. Thank you for listening to this episode of My AP Biology Thoughts. For more student-ran podcasts and digital content, make sure that you visit http://www.hvspn.com (www.hvspn.com). See you next time! Music Credits: "Ice Flow" Kevin MacLeod (incompetech.com) Licensed under Creative Commons: By Attribution 4.0 License http://creativecommons.org/licenses/by/4.0/ Subscribe to our Podcasthttps://podcasts.apple.com/us/podcast/my-ap-biology-thoughts/id1549942575 (Apple Podcasts) https://open.spotify.com/show/1nH8Ft9c9f6dmo75V9imCk (Spotify) https://podcasts.google.com/search/my%20ap%20biology%20thoughts (Google Podcasts )   https://www.youtube.com/channel/UC07e_nBHLyc_nyvjF6z-DVg (YouTube)   Connect with us on Social Media Twitterhttps://twitter.com/thehvspn ( @thehvspn) References​​Genetic Science Learning Center. (2017, August 1) Meet the Threespine Stickleback. Retrieved  October 13, 2021, from https://learn.genetics.utah.edu/content/evolution/meet (https://learn.genetics.utah.edu/content/evolution/meet) Robert Sanders, M. R., & Sanders, R. (2021, June 21). Stickleback fish provide genetic road map for rapid evolution. Retrieved from https://news.berkeley.edu/story_jump/stickleback-fish-provide-genetic-road-map-for-rapid-evolution/ Shen, H. (2012, April 04). Stickleback genomes reveal path of evolution. Retrieved from https://www.nature.com/articles/nature.2012.10392

My AP Biology Thoughts  Unit 7 Natural Selection EPISODE TITLE: Antibiotic Resistance Welcome to My AP Biology Thoughts podcast, I am Emily Greenberg and I am Angelina Graf and we will be your hosts for “Unit 7 Heredity: Examples of Evolution-antibiotic resistance”. In episode 113, we will be discussing antibiotic resistance and how it relates to the AP Biology Curriculum.  Segment 1: Overview of antibiotic resistanceAntibiotics are drugs that fight infections that are caused by bacteria Antibiotic resistance is when bacteria and germs build up resistance to the medications that are meant to kill them Antibiotic resistant germs are often very difficult to treat and dangerous infections can emerge A common misconception is that antibiotic resistance means that the body is resisting antibiotics, however it is actually the bacteria that is becoming resistant to antibiotics Overuse of antibiotics is one of the main causes of antibiotic resistance Segment 2: Evidence that supports antibiotic resistance Antibiotics also kill good bacteria that help to protect the body from infection Antibiotic resistant germs can spread throughout healthcare facilities, the environment, and other communities. The action of an antibiotic is an environmental pressure  Species have to adapt and evolve in order to survive these pressures We know that evolution is happening because bacterial infections can continue to spread even with the presence of antibiotics Penicillin resistance:  In WWI, penicillin treatment was used to treat the wounded and by some smaller civilian populations Biochemists began reporting resistance to it before the war was over and found a penicillin-inactivating enzyme secreted from a particular bacteria. Over the next few decades, overuse and repeated exposure to antibiotics helped the selection and replication of antibiotic resistant strains of bacteria Segment 3: Connection to the CourseAntibiotic resistance evolves as a result of natural selection and genetic mutation Bacteria that develop mutations that are resistant to antibiotics are more likely to survive and reproduce; this means that they are more fit If resistant bacteria reproduce with other resistant bacteria, their offspring will be fully resistant and this trait will become more frequent in the gene pool Overall, antibiotic resistance is dangerous because bacteria can develop resistance to extremely high amounts of antibiotics in a short amount of time which would leave patients very difficult to treat It's crucial to understand Antibiotic resistance to ensure that harmful antibiotic resistant bacteria don't evolve faster than our ability to treat them Thank you for listening to this episode of My AP Biology Thoughts. For more student-ran podcasts and digital content, make sure that you visit http://www.hvspn.com (www.hvspn.com). (Enter your closing Tag-line)! Music Credits:"Ice Flow" Kevin MacLeod (incompetech.com) Licensed under Creative Commons: By Attribution 4.0 License http://creativecommons.org/licenses/by/4.0/ Subscribe to our Podcasthttps://podcasts.apple.com/us/podcast/my-ap-biology-thoughts/id1549942575 (Apple Podcasts) https://open.spotify.com/show/1nH8Ft9c9f6dmo75V9imCk (Spotify) https://podcasts.google.com/search/my%20ap%20biology%20thoughts (Google Podcasts )   https://www.youtube.com/channel/UC07e_nBHLyc_nyvjF6z-DVg (YouTube)  Connect with us on Social Media Twitterhttps://twitter.com/thehvspn ( @thehvspn)

My AP Biology Thoughts  Unit 7 Natural Selection EPISODE TITLE: The Evolution of CoywolvesKeenan: Welcome to My AP Biology Thoughts podcast, my name is Keenan Wallace and I am your host for this podcast. In episode 115, we will be discussing the topic of Coywolves and how they relate to the AP Biology Curriculum.  Keenan: For this episode, we've brought in Alex Profit and Serena Russel to discuss the evolution of coywolves. So, to start us off: what exactly is a Coywolf? Alex: Well, ‘Coywolf' is actually just a nickname for what is known to the scientific community as an eastern coyote. Eastern coyotes are hybrids of coyotes, wolves and dogs, however they are still primarily coyotes and remain as coyotes rather than wolves.  Keenan: So you say that the Coywolves, or eastern coyotes are a mix of several different species. Do you know the genetic breakdown? Serena: It's difficult to say for certain since the coyotes' genetic makeup varies by region and population, but according to a DNA analysis done by Evolutionary Biologist Javier Monzón, they are 64% coyote, 13% gray wolf, 13% eastern wolf, and 10% dog.  Keenan: Wow, that's some genetic diversity. So how do these new hybrids differ from their pure coyote ancestors? Alex: For one thing, they're larger. Eastern Coyotes are 35-37% larger than their western counterparts. They also have larger and more powerful heads, their ears are more rounded like a wolf's and they have wolf-like fur markings. There's lots of variation within and between populations, but coywolves' features tend to match the midpoint between coyotes and wolves.  Keenan: Fascinating! So from what I understand, this interbreeding is a fairly recent development. What led to it? Serena: This story started several hundred years ago with the arrival of Europeans in the Americas. When Europeans colonized the East Coast of America they started cutting down forests and hunting large prey in the region, which threatened the habitat and food source of local grey wolves. At the same time, western coyotes, which are adapted to more open terrain, were drawn east by the expansion of their preferred habitat via deforestation. With shrinking numbers of grey wolves and a new thriving population of coyotes in the region, it makes sense that the wolves soon turned to coyotes as mating partners.  Serena: From there, natural selection took over. With the right mix of coyote and wolf DNA, a new species was created that was the best of both worlds. These “coywolves,” as they are called, are larger than coyotes, but inherited the social nature of wolves, meaning they form packs to hunt, which allows them to hunt large animals like deer in addition to the small prey that coyotes usually feed on. On top of that, they possess the strong ability of coyotes to adapt to urban environments, and are comfortable in both open and forested environments.  Keenan: I can see why this mixing would be beneficial, but is it considered evolution, or just hybridization?  Serena: Both. Coywolves have certainly evolved, but they have done so through the process of hybridization. The Coywolf, or eastern coyote was created from a mix of different species, but has diverged enough from the parent species that many believe it should be treated a separate species, though no official decision has yet been made on this matter.  Keenan: So coywolves aren't considered a separate species? Serena: Not yet. Coywolves have only been around for a few hundred years and are still in the earlier stages of their development, but many believe that they deserve to be recognized as their own species and will be soon.  Keenan: From what you've said, I'm sure it won't be long before scientists acknowledge them. So you've told us all about the specifics of coywolves, but how does their development link into the larger picture of evolution that we discuss in AP Bio? Alex: Coywolves are, of course, only a...

My AP Biology Thoughts Unit 7 Natural Selection EPISODE TITLE: Babiana ringens Welcome to My AP Biology Thoughts podcast, my name is Raelynn and my name is Samiyah and we are your hosts for Unit 7: Examples of Evolution - Plants and Birds. In episode 118, we will be discussing the plant Babiana ringens and how it has evolved to attract sunbirds. Segment 1: Overview of Babiana ringens and evolution to attract birdsThe Babiana ringens plant in South Africa evolved in such a way that increases the chance of  Nectarine famosa, or the malachite sunbird - their main pollinators- to stop by and drink nectar out of their flowers. In the certain region that these plants reside, most sunbirds avoid predators by staying away from the ground- as such, the Babiana ringens evolved to create a small perch, making it easier for birds to drink their nectar, and thus pollinate them, which in turn increased their evolutionary fitness.  Segment 2: Evidence that supports the evolution of Babiana ringens to attract pollinatorsThrough a study conducted by botanist Spencer Barrett from the University of Toronto Canada, along with a team of researchers, they found that the sunbirds in the specific region of South Africa in which the plants with the perches reside used the perches to pollinate the plants, and were their main pollinators.  They went on to study other Babiana ringens plants across South Africa and found that they didn't have the perches, and after studying them for some time, realized that their main pollinators weren't the sunbirds that require the perches to make pollination easier. As such, the perch was an adaptation to the environmental pressures (of their main pollinators having been sunbirds).  Segment 3: Connection to the CourseThe interactions between Babiana ringens and sunbirds demonstrate the concept of evolution and natural selection. The flowers with the perch were more “fit” for the environment since it encouraged the birds to perch on them and pollinate the flower. As a result, the Babiana ringens with the genes for the perch were able to both outlive and outpopulate those without perches. Over time, the gene for flowers without this stem faded away from the gene pool, and it became characteristic of Babiana ringens to have upside-down flowers.  IntroductionWelcome to My AP Biology Thoughts podcast, my name is Raelynn and my name is Samiyah and we are your hosts for this episode on Plants and Birds. Today we will be discussing Babiana ringens - a flower that has evolved to grow upside down to attract sunbirds, with data from BBC, nerdfighteria, and the National Center for Biotechnology Information. We would also like to thank Botanist Spencer Barett from the University of Toronto and his team of researchers for their findings on this subject! Quick Overview of Babiana RingensBabiana ringens, also known as rat's tail, is a plant native to Cape's Province, South Africa. It is a bright red perennial plant that flowers during the winter seasons (because it's a rebel). This plant is pollinated mostly by Nectarine famosa, or the malachite sunbird, which is named after its striking and vivid colors.  Babiana ringens are known for their peculiar and unique shape. Unlike other plants, its stem dips downwards towards the ground while the flower remains right-side-up.  How did this plant species evolve to grow this way, and what role did the malachite sunbirds play? Evolution of Babiana RingensGerman botanist Rudolf Marloth was the first to note that the Babiana ringens had seemed to evolve some sort of perch at their bottoms. To explore this odd phenomenon, botanist Spencer Barett from the University of Toronto, along with a team of researchers, conducted extensive research to understand the history behind the unique perches characteristic of the Babiana ringens plants.  They found that the plants in one specific geographic region only had one primary...

Welcome to My AP Biology Thoughts podcast, my name is Stefanie Ribecca and I am your host for episode # 104 called Unit 5 Heredity: Chromosomal Inheritance. Today we will be discussing how inheritance occurs in the chromosomal level.  Segment 1: Introduction to Chromosomal InheritanceChromosomal inheritance is an extension of Mendelian genetics.  Chromosomes contain DNA which carry the genetic information that code for proteins.  Chromosomes are found in pairs, and increase genetic variation during meiosis. Segment 2: More About Chromosomal InheritanceDuring meiosis, non sister chromatids in homologous pairs exchange information during crossing over. Certain genes may be close together on the chromosome and may appear to be inherited together.  Segment 3: Connection to the CourseChromosomal inheritance allows for a combination of traits from both parents.  Genetic diversity from chromosomal inheritance allows individuals in a population to adapt to the environment.    Thank you for listening to this episode of My AP Biology Thoughts.   For more student-ran podcasts and digital content, make sure that you visit http://www.hvspn.com (www.hvspn.com).   Music Credits:"Ice Flow" Kevin MacLeod (incompetech.com) Licensed under Creative Commons: By Attribution 4.0 License http://creativecommons.org/licenses/by/4.0/ Subscribe to our Podcasthttps://podcasts.apple.com/us/podcast/my-ap-biology-thoughts/id1549942575 (Apple Podcasts) https://open.spotify.com/show/1nH8Ft9c9f6dmo75V9imCk (Spotify) https://podcasts.google.com/search/my%20ap%20biology%20thoughts (Google Podcasts )   https://www.youtube.com/channel/UC07e_nBHLyc_nyvjF6z-DVg (YouTube)   Connect with us on Social MediaTwitterhttps://twitter.com/thehvspn ( )https://twitter.com/thehvspn (@thehvspn)

My AP Biology Thoughts  Unit 6 Gene Expression and RegulationWelcome to My AP Biology Thoughts podcast, my name is Morgan and I am your host for episode # 106 called Unit 6 Gene Expression and Regulation: DNA Replication. Today we will be discussing the process by which cells replicate their DNA Segment 1: Introduction to DNA Replication Difference between prokaryotic and Eukaryotic DNA P is one circular piece of dna where eukaryotic are multiple linear chromosomes DNA replication is semi-conservative Double helix is split in two and then each new strand is synthesized so to new double helices are made, each with one old and one new strand  very complex but very fast Extremely accurate (only 1 in a billion bases are messed up) Have to prime the DNA for replication Primers are short molecules that attach to the dna at the origin of replication  Mde by the enzyme primase Helicase is the enzyme that unwinds the double helix- initiates the replication fork (where two strands split apart) Multiple replication forks in eukaryotic dna Topoisomerase checks problems in the DNA before replication and maintains the structure DNA polymerase is the enzyme that synthesizes the new DNA strand- reads the bases and matches up complementary nucleotides Segment 2: More About the process of replication Replication initiation can occur at both directions from the origin where the primer binds DNA polymerase can only add nucleotides in the 5 to 3 prime direction, and read the strand of dna in the 3 to 5 prime direction Leading strand is continuous Lagging strand is discontinuous, has to read and synthesize in short segments (okazaki fragments) Enzyme ligase seals together the fragments Energy needed for this process (remember forming bonds between the nucleotides requires energy)  Segment 3: Connection to the Course Connection to mitosis S phase of mitosis is dna replication Necessary for cell division to make the same amount of chromosomes in daughter cells Process is close to the same for rna synthesis Leading and lagging strands Okazaki fragments and 3 to 5 prime direction vs 5 to 3 prime direction Thank you for listening to this episode of My AP Biology Thoughts. For more student-ran podcasts and digital content, make sure that you visit http://www.hvspn.com (www.hvspn.com).  Music Credits: "Ice Flow" Kevin MacLeod (incompetech.com) Licensed under Creative Commons: By Attribution 4.0 License http://creativecommons.org/licenses/by/4.0/ Subscribe to our Podcast https://podcasts.apple.com/us/podcast/my-ap-biology-thoughts/id1549942575 (Apple Podcasts) https://open.spotify.com/show/1nH8Ft9c9f6dmo75V9imCk (Spotify) https://podcasts.google.com/search/my%20ap%20biology%20thoughts (Google Podcasts )   https://www.youtube.com/channel/UC07e_nBHLyc_nyvjF6z-DVg (YouTube)   Connect with us on Social Media Twitterhttps://twitter.com/thehvspn ( @thehvspn)

My AP Biology Thoughts  Unit 6 Gene Expression and RegulationWelcome to My AP Biology Thoughts podcast, my name is Sid and I am your host for episode #112 called Unit 6 Gene Expression and Regulation: Biotechnology. Today we will be discussing how we use technology to study how the mechanisms of DNA and gene expression work. Segment 1: Introduction to BiotechnologyThe four main processes used in biotechnology that relate to this unit are bacteria transformation, PCR, electrophoresis, and DNA sequencing. Bacterial transformation makes multiple copies of a recombinant DNA molecule. PCR is used to produce millions of copies of a DNA sequence from an initial sample. Electrophoresis separates DNA and RNA molecules by their size and their electrical charge. DNA sequencing is used to determine the sequence of the bases in a DNA molecule. Segment 2: More About BiotechnologyFirst we'll talk about bacterial transformation. The process of bacterial transformation starts with mixing the prepared bacteria with DNA. Then the bacteria are heat shocked. This allows them to take up a plasmid. The bacteria that take up the plasmid become resistant to antibiotics, so we place all of the bacteria on an antibiotic plate. The ones that survive are the ones that are known to have taken up the plasmid since they survived the antibiotic. The bacteria without the plasmid end up dying. The bacteria that survived end up being used to create a cluster of identical bacteria that also contain the plasmid. The colony containing the plasmid is grown and used to produce the plasmid or proteins. Another form of biotechnology is PCR. To begin, the main ingredients (taq polymerase, primers, template DNA, nucleotides, and cofactors) are all added in a tube. The first step of PCR is denaturation. In denaturation the reaction is heated so that the DNA strands separate and create single strands. The next step is annealing where the reaction is cooled so that the primers bind to the complementary sequence on the DNA strands. The third step is extension. In this step the temperature is raised again so that the taq polymerase starts at the primers and synthesizes new strands of DNA. This cycle repeats between 25-35 times which ends up creating millions of copies of the same DNA region. Electrophoresis is another form of important bio technology. In electrophoresis, DNA samples are placed into indentations at one end of a gel. THis gel gets an electric current applied to it. Since DNA fragments are negatively charged, they move towards the positive electrode. Because the DNA fragments have the same charge, the smaller fragments are able to move through the gel faster than the large ones. This allows the DNA to be separated by size. The gel is then stained with a DNA binding dye which makes the DNA fragments appear as bands so that they can be observed. The last thing we are going to talk about is DNA sequencing. In DNA sequencing, the DNA strand goes through bacterial transformation so that we can produce many copies of it in a plasmid. The DNA is then isolated and goes into a plate with other ingredients like the DNA bases, DNA polymerase, primers, and modified bases labeled with colored fluorescent tags called terminator bases. This mixture then goes through a process very similar to PCR. The difference is when polymerase adds the bases, it eventually adds a terminal base which makes it so that no more bases can be added to the strand of DNA. This then produces lots of fragments of DNA at different lengths. Then when we separate them by size through electrophoresis, we can figure out where the beginning of the sequence is. When the fragments are separated in the gel, a laser reads the terminator base of each strand which gives us the full sequence of bases Segment 3: Connection to the Course It's important for us to know how these different processes work because it helps us understand how we apply the things we know about gene expression and...

My AP Biology Thoughts  Unit 5 HeredityWelcome to My AP Biology Thoughts podcast, my name is Adrienne Li and I am your host for episode #99 called Unit 5 Heredity: Mendelian Genetics. Today we will be discussing Mendel's experiment with pea plants, and the three laws he proposed from his results. Segment 1: Introduction to Mendelian GeneticsFirst off, lets define what mendelian genetics is. It's a concept about heredity that was formed by Gregor Mendel and states that genes are distinct units that come in pairs and are inherited independently from other genes. These make up an offspring's genome and provide the basis of inheritance for sexual reproduction. Now, Mendel didn't just come up with this concept randomly. It started with an experiment he conducted where he crossbred pure pea plants with different traits such as purple vs. white flowers and tall vs. short stems. The F1 generation all carried the same trait as one of the parents, which refuted the prior notion that inheritance was a blend of the parent's traits since the flowers weren't pink. What was more strange was the F2 generation, which had a 3:1 ratio where 3 individuals had the same trait as one parent and 1 individual had the other parent's trait.  Segment 2: More About Mendelian GeneticsFrom these experimental results, Mendel summarized his findings in 3 laws. The first one is the law of dominance where genes have two alleles, and the dominant allele will conceal the recessive allele. This was seen in the F1 generation where all the flowers were purple even though one of the parents had white flowers. This meant that purple was dominant while white was recessive, thus only the purple flower trait was expressed. The F2 generation with a 3:1 ratio further confirmed this concept because breeding heterozygotes results in 4 offspring, one that is homozygous dominant, two that are heterozygous, and one that is homozygous recessive which means 3 individuals will express the dominant trait and one will express the recessive trait. Next, the second law is the law of independent assortment which states that alleles of two or more different genes are sorted into gametes independently of another where the allele a gamete receives for one gene does not influence the allele receive for another. This idea was demonstrated when he performed dihybrid crosses which tested two different traits and it resulted in a 9:3:3:1 ratio. This showed that traits such as flower color and stem length are inherited independently from each other, and one does not influence how the other trait is inherited. Lastly, the law of segregation says that during reproduction, the gametes only receive one copy of a gene from each parent at random. This was demonstrated by his 3:1 ratio where during segregation in meiosis of the F1 generation, each gamete acquired one of the two genes so that there were three possible combinations, either homozygous dominant, heterozygous, or homozygous recessive. Since there were two ways to form heterozygotes, either receiving one dominant and one recessive allele from either parent, and because heterozygotes and homozygous dominant gametes express the same phenotype, it supported the 3:1 ratio and law of segregation.  Segment 3: Connection to the CourseTying this back to the overall ideas in Unit 5, mendelian genetics corroborates the concept of genotypes, phenotypes, and punnett squares. Genotypes are the pairs of alleles that an individual has, such as one purple flower and one white flower allele, whereas phenotypes are the expressed traits which in this example would be a purple flower. This makes sense because of mendelian genetics and the law of dominance, where the dominant allele which is purple flowers, conceals the recessive white flower allele. As for punnett squares, the reason why we can use them to predict mendelian inheritance patterns is because of the law of segregation and independent assortment. The law of segregation

My AP Biology Thoughts  Unit 5 HeredityWelcome to My AP Biology Thoughts podcast, my name is Chloe McGregor and I am your host for episode #107 called Unit 6 Gene Expression and Regulation: transcription and RNA processing. Today we will be discussing the process of transcription, and how MRNA is processed on its way to the ribosomes.  Segment 1: Introduction to Transcription and RNA Processing The central dogma is the process by which the genetic information stored in DNA is converted into functional products such as proteins. This process consists of 3 steps: transcription, translation, and protein synthesis. In this episode, I will specifically discuss transcription, the process of transcribing shorter segments of DNA into mRNA strands. However, once these mRNA strands are created, there are still steps that take place to ensure that the strand is mature and ready to be translated. This is called RNA processing. The mRNA strand is manipulated into a mature strand through a series of processes, and is then ready to travel to the ribosomes for translation and protein synthesis. Segment 2: More About Transcription and RNA Processing As I mentioned earlier, transcription is the first step and this is when the DNA strand is read, and a new complementary mRNA strand is synthesized. DNA is composed of different nitrogenous bases compared to RNA. DNA consists of adenine, thymine, cytosine, and guanine. However, RNA contains uracil instead of thymine. Base pairing rules are used by RNA polymerase to synthesize a new strand using the information on the unzipped DNA strand. Transcription is very important because DNA is very unique and one of a kind, so this single strand of RNA makes it possible for the genetic information to stay safe, but also be used for protein synthesis outside of the nucleus. Following transcription, RNA processing occurs. Premature mRNA strands contain both introns and exons that are transcribed from the DNA, however, the introns are spliced out to create a concise and mature strand of RNA that is ready to be translated. Introns are removed to ensure that the correct protein is being created during protein synthesis because a mistake in the RNA strand can cause mistakes during translation. Also, if introns are kept on accident, the wrong protein can be produced which will disrupt many different cellular processes. RNA splicing is also the reasoning behind one strand of DNA coding for so many different proteins depending on which introns are spliced out, and which exons are kept in the sequence.  Segment 3: Connection to the Course Transcription and RNA processing play a major role in healthy cellular function and bodily function in general. Because specific proteins and enzymes are so vital to so many different processes that are happening simultaneously, it is important that transcription and RNA processing are happening precisely and efficiently to keep the body functioning. The idea of RNA processing is also important because it can provide different proteins from the same gene depending on what the body is in need of. Overall, these processes may seem small, but they play such a large role in kickstarting protein synthesis and making sure that the RNA strands are accurate and ready to be converted into proteins.  Thank you for listening to this episode of My AP Biology Thoughts. For more student-ran podcasts and digital content, make sure that you visit http://www.hvspn.com (www.hvspn.com).  Music Credits: "Ice Flow" Kevin MacLeod (incompetech.com) Licensed under Creative Commons: By Attribution 4.0 License http://creativecommons.org/licenses/by/4.0/ Subscribe to our Podcast https://podcasts.apple.com/us/podcast/my-ap-biology-thoughts/id1549942575 (Apple Podcasts) https://open.spotify.com/show/1nH8Ft9c9f6dmo75V9imCk (Spotify) https://podcasts.google.com/search/my%20ap%20biology%20thoughts (Google Podcasts )  ...

My AP Biology Thoughts  Unit 5 HeredityWelcome to My AP Biology Thoughts podcast, my name is Corrinna and I am your host for episode #100 called Unit 5 Heredity: X-Linked Inheritance & Polygenic Inheritance. Today we will be discussing how X-linked inheritance and polygenic inheritance work. Segment 1: Introduction to X-Linked Inheritance & Polygenic InheritanceX-linked and polygenic are both different types of non-mendelian inheritance. Mendelian inheritance follows the laws of segregation and independent assortment, so X-linked and polygenic traits by definition do not follow these laws.  X-linked traits are traits whose alleles are carried on the sex chromosomes instead of the normal chromosomes. Males have XY sex chromosomes, and females have XX sex chromosomes. In x-linked inheritance, the allele for a trait is only carried on the x chromosome. This means that any male who inherits the allele will express the trait since he only has one copy of the x chromosome. X-linked traits can be dominant or recessive, just like in mendelian inheritance. However, since the alleles are located on the x chromosome, any male who gets the linked allele will express the trait. In females, x-linked inheritance works like mendelian inheritance - if both x chromosomes have the recessive allele, it is expressed, otherwise the dominant allele will always be expressed. Polygenic inheritance is when a single phenotypic trait is controlled by multiple genes. This is different from multiple alleles because in polygenic inheritance, all of the polygenic genes can be found in an individual, while in multiple alleles, only two of the alleles are present in an individual. Polygenic inheritance also produces a range of phenotypes, rather than specific distinct phenotypes. Polygenic inheritance also doesn't exhibit complete dominance, which is why there is a range of phenotypes.  Segment 2: More About X-Linked Inheritance & Polygenic InheritanceOne example of an x-linked trait is hemophilia. In males who possess the altered copy of the gene, they will always express the phenotype for hemophilia because they only have one copy of the X chromosome. However women need two copies of the altered gene to express the phenotype. This is because hemophilia is an x-linked RECESSIVE trait. If it was x-linked dominant, the woman would only need one copy of the altered gene to express the phenotype. Polygenic inheritance includes traits like hair color, height, and skin color, as well as non visible traits like blood pressure and intelligence. Skin color is one example of this. Skin color is controlled by the pigment melanin, and darker skin results from more melanin. Hypothetically, the production of melanin is controlled by contributing alleles which will be called A, B, and C, which results in dark skin color. The non contributing alleles lowercase a, b, and c, produce a light skin color. Since polygenic alleles don't display dominance, each contributing allele gives an additive effect in which the different alleles create a spectrum of possible phenotypes. In this example, individuals with all uppercase alleles will have the darkest skin, and individuals with all lowercase alleles will have the lightest skin color.  Segment 3: Connection to the CourseX-linked and polygenic inheritance are very common. Although most people only learn about Mendelian inheritance, x-linked and polygenic traits are still prevalent and control many prominent phenotypic traits, such as hair and skin color, as well as susceptibility to diseases.  X-linked and polygenic traits prove that mendelian inheritance isn't the most important pattern of inheritance, even if it may be the most commonly known. Because x-linked traits often determine an individual's susceptibility to diseases, they are extremely important to understand. Additionally because polygenic inheritance is easily seen in people's skin and hair color, it is...

My AP Biology Thoughts  Unit 6 Gene Expression and RegulationWelcome to My AP Biology Thoughts podcast, my name is Shriya Karthikvatsan and I am your host for episode #110 called Unit 6: Gene Expression and Regulation. Today we will be discussing the mechanisms used by cells to increase or decrease the production of specific gene types, and how this fits into the overarching unit.  Segment 1: Introduction to Gene Expression and RegulationWe will begin by going over a few helpful terms and ideas to provide context for the topic of gene expression and regulation which is a pretty broad topic as a whole A gene consists of a string of DNA hidden in a cell's nucleus, and what we will unpack is how it knows when to express itself and cause the production of a string of amino acids called a protein The overall process is that a string of DNA is expressed to make RNA Then, something called mRNA is translated from nucleic acid coding to protein coding to form a protein  In terms of regulation, genes can't control an organism on their own so they must interact with and respond to the organism's environment  Some genes are always “on” regardless of environmental conditions, and these genes are among the most important elements of the genome because they control the ability of DNA to replicate, express itself, repair itself, and perform protein synthesis Overall, regulated genes are needed occasionally and get turned “on” or “off”  Regulation differs between prokaryotes and eukaryotes because in prokaryotes, most regulatory proteins are negative and turn genes off  In eukaryotes, cell-cell differences are determined by expression of different sets of genes This means that an undifferentiated fertilized egg looks and acts quite different from a skin cell, a neuron, or a muscle cell because of differences in the genes each cell expresses  In the next segment we will go into further detail of the specific processes involved in expression and regulation  Segment 2: More About Gene Expression and RegulationGene expression begins with transcription which makes mRNA and the overall process is the same in both prokaryotes and eukaryotes  Prokaryotes lack a nuclear envelope, and eukaryotes use an extra step called RNA processing where RNA is edited and introns are edited out and exons are spliced together It is catalyzed by RNA polymerase which separates DNA strands and links RNA nucleotides at the 3' end (side notes: prokaryotes have 1 type of polymerase and eukaryotes have 3) Transcription is initiated when RNA polymerase binds to a promoter and unwinds the DNA strands Initiation site and a small sequence after are recognized by transcription factors which are proteins that bind to promoter and guide RNA polymerase to bind to TATA box  Then, mRNA carries the genetic code and mRNA itself is a series of codons In eukaryotes, mRNA processing works by the 5' end getting a GTP cap and the 3' end getting a poly-A tail  Also, a splicesome complex of SnRNPs + a protein work together to cut out the introns (intruding codons) and splice the exons (expressed codons) together Following transcription, translation occurs in the ribosome after mRNA brings the genetic code and it is when tRNA brings the amino acid and the ribosome is able to be completely assembled Translation is initiated by a small subunit of the ribosome which binds to a recognition site on the mRNA and an anticodon of tRNA initiator binds to a start codon The next part of translation is elongation in which the anticodon of the next tRNA binds to a codon at the A site and the polypeptide bonds the 2nd amino acid onto the 1st amino acid (this process repeats until a stop codon is reached) Finally, termination is when the stop codon reaches the A site and a release factor frees the tRNA from the P site and disconnects the polypeptide causing everything to separate After translation, the protein is modified

My AP Biology Thoughts  Unit 6 Gene Expression and RegulationWelcome to My AP Biology Thoughts podcast, my name is Jacqueline Sun and I am your host for episode #105 called Unit 6 Gene Expression and Regulation: DNA and RNA Structure. Today we will be discussing the central structural components of DNA and RNA as well as the similarities and differences between the two. Segment 1: Introduction to DNA and RNA Structure Deoxyribonucleic acid, DNA, and ribonucleic acid, RNA, are two of the most important biological molecules for survival DNA responsible for carrying genetic information is commonly considered the “blueprint” for life's functions. Its basal structure, a double helix that is unique from RNA, is key to its ability to replicate itself. DNA, when not undergoing replication, is coiled up into compact structures known as chromosomes. They are wrapped around histone proteins: the degree of tightness to which they are wrapped determines how much of the DNA is expressed. RNA builds off of DNA and creates a template from which proteins can be created in ribosomes. Because they are based off of a parent DNA strand, RNA has a single strand instead of two. Segment 2: More About DNA and RNA Structure However, there is much more to DNA and RNA Structure than the helical strands. Lets first focus on what makes up the strands for DNA and RNA: Both DNA and RNA have a sugar-phosphate backbone that is key to holding the entire molecule together.  However, the sugar in DNA is deoxyribose sugar, from which it derives its name. The sugar in RNA is ribose sugar, which has one more hydroxyl group than the sugar in DNA.  The sugar and phosphate group in DNA and RNA alternate repeatedly. They link with a special directionality that is often denoted with a 5' and 3' end. This is a rather abstract concept, but basically the 5' and 3' indicate which carbon in a sugar molecule the phosphate group will attach itself, forming the repeating phosphate-sugar backbone. Another central structural component are the nitrogenous bases found in both DNA and RNA, with one key difference. DNA has the bases adenine, cytosine, guanine, and thymine. Adenine and guanine are known as purine bases, while cytosine and thymine are the pyrimidine bases. Purines tend to be larger than pyrimidines because purines have a double ring structure as opposed to pyrimidine's single ring structure. Only purines and pyrimidines can bind together. Specifically, in DNA, adenine and thymine bind together, while cytosine and guanine bond together. They are held together by hydrogen bonds which link not only the bases, but also the two strands of DNA to form a double helix. The 1:1 ratio by which the nitrogenous bases bond (adenine=thymine, guanin=cytosine) explains how DNA molecules are able to replicate by synthesizing a new strand from a parent strand. RNA has the same bases of adenine, cytosine, and guanine, but the key difference is that it has uracil instead of thymine. Its purines are still adenine and guanine, but it's pyrimidines are cytosine and uracil. Adenine will match with uracil as opposed to thymine in RNA synthesis. Lengthwise, DNA tends to be significantly longer than RNA. This is because while RNA is based on DNA, it will not code for the entire strand but only a certain segment of a strand. As a result, an RNA strand may only be a few thousand base pairs long, while DNA can reach from hundreds of thousands to millions of pairs long. There are also coding and non coding regions of DNA that are transcribed into RNA. The coding regions of DNA known as genes are the ones that can serve as templates for the synthesis of proteins, while the non coding regions have no role in creating proteins. However, non coding regions are still important. They provide structural support to the DNA molecules and also may act as regulators for gene expression. When DNA is transcribed in RNA, the coding regions become known as exons...

My AP Biology Thoughts  Unit 6 Gene Expression and RegulationWelcome to My AP Biology Thoughts podcast, my name is Saarim Rizavi and I am your host for episode #108 called Unit 6 Gene Expression and Regulation: Translation. Today we will be discussing everything there is to know about translation. I will first be giving a brief overview of what translation is, it's overall function, the 3 steps involved in translation, and some of the different components and organelles involved in translation. I'll then go into greater detail on the individual steps of translation which will involve the organelles and different components mentioned before. Finally, I will relate the process of translation to the broader topic of gene expression and regulation. Before I begin, I would like to give credit to Khan Academy, biologydictionary.com, and nature.com for the information they provided me with in order for this podcast to be possible. So thanks to them. Alright, so here we go: Segment 1: Introduction to TranslationTranslation is the process of creating proteins from an mRNA template A cell reads information from mRNA molecules and uses this information to build a protein - involves decoding an mRNA and using its information to build a polypeptide, and multiple polypeptide chains form a protein Three basic steps of translation - initiation, elongation, and termination Initiation - the ribosomes get together with the mRNA and the first tRNA so translation can begin Elongation - the amino acids are brought to the ribosome by tRNAs and linked together to form a chain of amino acids Termination - the finished polypeptide is released to go and do its job in the cell In mRNA, the instructions for building a polypeptide come in groups of 3 nucleotides called codons - there are 61 codons for amino acids and each of them is read to specify a certain amino acid out of the 20 possible amino acids Stop codons tell the cell when polypeptide is complete and the AUG codon is the start codon which signals the start of protein construction In translation, the codons of an mRNA are read in order, from the 5' end to the 3' end, by tRNAs. tRNA's = molecular bridges that connect mRNA codons to the amino acid they encode One end of the tRNA has a sequence of 3 nucleotides called an anticodon, which binds to a matching mRNA codon through base pairing; the other end of the tRNA carries the amino acid specified by the codons tRNAs bind to mRNAs inside the ribosomes - ribosomes are made up of protein and ribosomal RNA The ribosomes provide a set of slots where tRNAs can find their matching codons on the mRNA template and deliver their amino acids. As these tRNAs enter slots in the ribosome and bind to codons, their amino acids are linked to the growing polypeptide chain in a chemical reaction. Segment 2: More About Translation Initiation Ribosome, an mRNA with instructions for the protein to be built, and an initiator tRNA carrying the first amino acid in the protein - these components come together to form the initiation complex which is the molecular setup needed to make a new protein The tRNA carrying the methionine attaches to the small ribosomal subunit - they bind to the 5' end of the mRNA by recognizing the 5' GTP cap which was added during processing in the nucleus They go along the mRNA in the 3' direction, stopping when they reach the start codon (eukaryotic cells) In bacteria, the small ribosomal subunit attaches directly to certain sequences in the mRNA - these Shine-Dalgarno sequences mark the start of each coding sequence, letting the ribosome find the right start codon for each gene. Elongation The amino acid chain gets longer and the mRNA is read one codon at a time, and the amino acid matching each codon is added to a growing protein chain Detailed: The first methionine- carrying tRNA (methionine is an amino acid specified by the start codon, AUG) starts out in the middle slot of the ribosome,...

My AP Biology Thoughts  Unit 5 HeredityWelcome to My AP Biology Thoughts podcast, my name is CJ and I am your host for episode #102 called Unit 5 Heredity: Different expressions of alleles. Today we will be discussing incomplete dominance, codominance and multiple alleles.  Segment 1: Introduction to expression of alleles Alleles are what make us unique, they code us and make us appear the way we are. In simple biology, we learn about how genotype affects phenotype and when we start off on this concept, we visualize a simple set of alleles. And when we first start to learn about alleles, we learn that dominant alleles override and affect the phenotype even if a recessive allele is present. Let's use ear lobes as an example; we can say attached earlobes are recessive and loose are dominant. If the offspring has attached earlobes and both parents have unattached earlobes, we see a perfect example of simple inheritance. We would typically draw out a punnett square. We cannot directly see what's the genotype of the parents, however we can assume that they are both heterozygous due to the nature that their offspring is homozygous recessive. When drawing out the Punnett square, we can see that there is a 50/50 chance that the offspring will have attached earlobes.  Segment 2: More About this However, nothing is ever that simple. As you can see, in the world around us, there are more than just two outcomes when it comes to anything living. In most cases, there are many more than just 2 phenotypes. The world is much more complicated than just dominant and recessive. That's where incomplete dominance, codominance and multiple alleles come into play. They show us that there is much more to life than just capital and lowercase letters.To start off, incomplete dominance has the same number of alleles as a standard dominant and recessive genotype. The main difference is that heterozygous organisms no longer just express the dominant allele, they express a phenotype that is in between homozygous dominant and homozygous recessive. A great example of this is some sort of flower. If there are three colors of flower, one red, one white and one pink. The red can be determined as the “dominant” while the white could be “recessive”, making any flower with heterozygous alleles pink. This represents incomplete dominance. And just like incomplete dominance, codominance is only made up of a single set of alleles too. However, instead of the phenotype being somewhere in the middle, for codominance, the phenotype for heterozygous is a mix of the two. Meaning if a species is represented by the genotype of one dominant and one recessive, they are going to express both phenotypes, in their own respective way. Now for when alleles get complicated. When there are multiple alleles, the same rules apply for simple dominance, where the heterozygous only expresses the dominant phenotype. However, there are more alleles that influence the phenotype as well. Depending on the trait, there could be 4 or more alleles that determine what a species looks like. Just like in eye color, where there are 16 different genes that determine what colors your eyes could be. And in theory you could use a Punnett square to determine the predicted offspring phenotypes, but that square would be substantially larger and more complicated as different letters are flying around.  Segment 3: Connection to the Course All in all, a variety of things can influence how a species can look. And the different expression of alleles can alter those looks even more. But that's all there for a cause. All of these alleles got there somehow, whether it be natural selection or a random mutation that had the benefit of the doubt. But these alleles can show us whether a recessive trait is more fit for one environment than another. All of this has a purpose, everything happens for a reason, and looking at alleles we can now predict what the outcomes could

My AP Biology Thoughts  Unit 5 HeredityWelcome to My AP Biology Thoughts podcast, my name is Nikki Evich and I am your host for episode #103 called Unit 5 Heredity Environmental Effect on Phenotype. Today we will be discussing how the environment can alter phenotypes. Segment 1: Introduction to Environmental Effect on PhenotypePhenotype is determined by genotype  Genotype and environment work together to determine phenotype temperature, oxygen levels, humidity, light cycles, and the presence of mutagens can all impact which of an animal's genes are expressed, which ultimately affects the animal's phenotype These can turn on and off genes Segment 2: More About Environmental Effect on Phenotype Fur color These rabbits and cats have a mutant allele for the coat color gene that is white The enzyme encoded by the gene is inactive at temperatures above about 35 degrees The extremities are cooler than the main body (around 25 degrees), so the fur on these regions is dark. Segment 3: Connection to the Course Environmental pressures drive diversity in ecosystems Phenotypic diversity is caused by not only genetics, but the environment as well A higher diversity in ecosystems allows populations to be better suited for sudden changes to their ecosystem Thank you for listening to this episode of My AP Biology Thoughts. For more student-ran podcasts and digital content, make sure that you visit http://www.hvspn.com (www.hvspn.com). Bye now! Music Credits: "Ice Flow" Kevin MacLeod (incompetech.com) Licensed under Creative Commons: By Attribution 4.0 License http://creativecommons.org/licenses/by/4.0/ Subscribe to our Podcast https://podcasts.apple.com/us/podcast/my-ap-biology-thoughts/id1549942575 (Apple Podcasts) https://open.spotify.com/show/1nH8Ft9c9f6dmo75V9imCk (Spotify) https://podcasts.google.com/search/my%20ap%20biology%20thoughts (Google Podcasts )   https://www.youtube.com/channel/UC07e_nBHLyc_nyvjF6z-DVg (YouTube)   Connect with us on Social Media Twitterhttps://twitter.com/thehvspn ( @thehvspn)

My AP Biology Thoughts  Unit 5 HeredityWelcome to My AP Biology Thoughts podcast, my name is Victoria Villagran and I am your host for episode #101 called Unit 5 Heredity: Linked Genes. Today we will be discussing linked genes and their characteristics! Segment 1: Introduction to Linked Genes Linked Genes A form of non-mendelian inheritance  Discovered by Thomas Hunt Morgan, using the fruit fly Drosophila melanogaster  Genes on the same chromosome, making them more likely to be inherited together  If crossing over occurs, then they are no longer linked it will look like independent assortment  If they are linked, they will not assort independently and the ratios of the offspring will different  If there are more parental phenotypes, then it is linked If there are more recombinant then is it non-linked  The recombination frequency is very small. If the genes are far apart on a chromosome, or on different chromosomes, the recombination frequency is 50%. ... If the recombination frequency is less than 50% we say the two loci are linked Recombinant and Map Units: The farther apart the genes are on the chromosome, the more likely they are to separate because of crossing over resulting in recombinant offspring  Recombinant offspring generally appear in proportions related to the recombination frequency between the two genes: Calculated by dividing the number of recombinant progeny by the total number of progeny  This can be used to calculate map units or how far away the genes are from each other  Segment 2: More About Linked Genes Let's look at fruit flies If linkage held true, then F1 would only have the two parental phenotypes in a 1:1 ratio  The genes for eye color and the genes for wing length are on the same chromosome, thus are inherited together.  A cross between gray and normal with black vestigial There are more parental phenotypes with 965 and 944 than recombinant with 206 for gray and vestigial, and 185 with black normal. There is an expected 575 frequency for each genotype  they are linked, so they did not assort independently and the ratios of actual offspring were different from the expected Segment 3: Connection to Heredity  Linked genes and heredity, specific non-mendelian inheritance are connected Heredity or inheritance is the passing on of traits or genetic information from one generation to the the next, and linked genes are a specific way how these genes are passed on from being on the same chromosome and not independently assorted, giving more parental phenotypes. For example, the farther apart the genes are on the chromosome, the more likely they are to separate because of crossing over resulting in recombinant offspring. The location and space between genes dictate the way they will be inherited by new generations.  Thank you for listening to this episode of My AP Biology Thoughts. For more student-ran podcasts and digital content, make sure that you visit http://www.hvspn.com (www.hvspn.com). Have a nice day! Music Credits: "Ice Flow" Kevin MacLeod (incompetech.com) Licensed under Creative Commons: By Attribution 4.0 License http://creativecommons.org/licenses/by/4.0/ Subscribe to our Podcast https://podcasts.apple.com/us/podcast/my-ap-biology-thoughts/id1549942575 (Apple Podcasts) https://open.spotify.com/show/1nH8Ft9c9f6dmo75V9imCk (Spotify) https://podcasts.google.com/search/my%20ap%20biology%20thoughts (Google Podcasts )   https://www.youtube.com/channel/UC07e_nBHLyc_nyvjF6z-DVg (YouTube)   Connect with us on Social Media Twitterhttps://twitter.com/thehvspn ( @thehvspn)

My AP Biology Thoughts  Unit 6 Gene Expression and RegulationWelcome to My AP Biology Thoughts podcast, my name is Arthur Kim and I am your host for episode # 111 called Unit 6 Gene Expression and Regulation: Mutations. Today we will be discussing what genetic mutations are, the different types, as well as some of the possible effects.   Segment 1: Introduction to Mutations A mutation is any change to a sequence of DNA. They're not always bad, as some mutations can arise that result in a more favorable phenotype. Mutations can also occur on the scale of chromosomes, often as a result in errors in meiosis. Segment 2: More About Mutations On a strand of DNA, there are two main types of mutations that can occur. Point mutations are the result of swapping one base pair for another. Very often, these aren't a big deal because only one amino acid will be affected or possibly unaffected since oftentimes more than one codon produces the same amino acid. In many cases, the protein that the mutated strand codes for will still be functional.   Frameshift mutations are the result of an insertion or deletion of a base pair in a strand of DNA. These are often detrimental because they completely change the codons in an entire sequence of mRNA. As a result, the protein will be synthesized with completely different amino acids than what they're supposed to be.   This causes the protein to be nonfunctional. Frameshift mutations are the cause of several deadly genetic diseases such as Tay Sachs and cystic fibrosis.   At the level of chromosomes, the types of mutations that can occur are deletions (part of the chromosome is lost), duplications (an extra copy of a part of a chromosome), inversions (the orientation of a segment of a chromosome is flipped), and translocation (two chromosomes exchange components).   Segment 3: Connection to the Course Genetic mutations are one of the main sources of variation within the gene pool. As a result, mutations are what allow for evolution to occur in populations, bringing about the diversity of life on Earth we see today.   Thank you for listening to this episode of My AP Biology Thoughts. For more student-ran podcasts and digital content, make sure that you visit http://www.hvspn.com (www.hvspn.com).  Music Credits: "Ice Flow" Kevin MacLeod (incompetech.com) Licensed under Creative Commons: By Attribution 4.0 License http://creativecommons.org/licenses/by/4.0/ Subscribe to our Podcast https://podcasts.apple.com/us/podcast/my-ap-biology-thoughts/id1549942575 (Apple Podcasts) https://open.spotify.com/show/1nH8Ft9c9f6dmo75V9imCk (Spotify) https://podcasts.google.com/search/my%20ap%20biology%20thoughts (Google Podcasts )   https://www.youtube.com/channel/UC07e_nBHLyc_nyvjF6z-DVg (YouTube)   Connect with us on Social Media Twitterhttps://twitter.com/thehvspn ( @thehvspn)

My AP Biology Thoughts  Unit 5 HeredityWelcome to My AP Biology Thoughts podcast, my name is Helena Holley and I am your host for episode #109 called Unit 6 gene expression and regulation: Regulation of gene expression. Today we will be discussing the mechanism of gene expressions and regulation in Eukaryotes and Prokaryotes. Segment 1: Introduction to Gene Expression and Regulation Gene expression and its regulation and control is essential for cell specialization in Eukaryotes. All cells have the same information, however their differences in function come from which genes they express. As you go through development cells are differentiated. The way this happens is by specific transcription factors and translation controls that tell the cells which genes they are expressing as you develop. Your basic genetics are not the only thing that determines which genes are expressed, epigenetics also plays a role. Certain environmental factors that occur in a parents lifetime can alter the gene expression of offspring. This happens when there are changes in the parents' cells that undergo meiosis to produce gametes. Examples of this include DNA methylation and histone modification. While I was just discussing eukaryotes above, gene expression and regulation is also important in prokaryotes, which I will discuss more later.  Segment 2: More About Gene Expression and RegulationThere are various ways in which gene expression is regulated in Eukaryotes. One regulation method is determined by how tightly DNA is wrapped around Histone proteins. The tighter the DNA is wrapped, the harder it is for transcription to take place, and certain enzymes can alter how tight or loose it is wrapped depending on what needs to happen. There are also chromatin-modifying enzymes that can make the DNA more or less accessible. Another regulatory factor is the Control elements which are regulatory sequences on DNA that control the expression of proteins. Alternative RNA splicing helps to regulate post transcription, as it produces different mRNA from the same gene. Another useful method is mRNA degradation which is used to break down mRNA if the protein is not needed to be expressed anymore. Finally, various regulatory proteins can block initiation of translation if that is needed. It is important to note that mRNA is not the only type of RNA used for regulation, and there are various types of non-coding RNA that have different functions in regulation of gene expression. In prokaryotes there are repressible and inducible operons. The repressible operon genes are able to be silenced, and the inducible operon genes are able to be turned on. This function of these operons is important in gene regulation because if a repressible operon is absent, the repressor is inactive and the operon will be produced. When too much of a repressible operon is in the cell, it will bind to the repressor which will bind to the operator, preventing any more from being produced. For inducible operons, the process works essentially the opposite of the repressible operons (so briefly the repressor is active when there is an absence of lac operon, and it is inactive when there is presence lac operon).  Segment 3: Connection to the CourseGene expression and regulation is important because any errors in regulation can lead to developmental problems. For example, If the tumor suppressor gene is silenced due DNA methylation occurring in the parent, the offspring would be very susceptible to cancer and disease. Another reason why the regulation of expression of genes is important is because not having all genes turned on all the time, conserves a lot of energy and space. It is a lot more efficient to only turn on genes when they are required. Additionally, if every gene was being expressed, cells would have to be much larger because DNA has to be unwound in order to transcribe and translate it.  Thank you for listening to this episode of My AP Biology...

My AP Biology Thoughts  Unit 5 HeredityWelcome to My AP Biology Thoughts podcast, my name is Nidhi and I am your host for episode # 97 called Unit 5 Heredity: Meiosis. Today we will be discussing what meiosis is, why it's important, and how it connects to other topics we've learned about this year.  Segment 1: Introduction to why Meiosis is important From what we have learned this year, we know Mitosis is used to prudence daughter cells that are genetically identical to a parent cell. On the other hand, the function of meiosis is to produce gametes. The daughter cells have half as many chromosomes as the parent. To put it in other words, a diploid cell is the parent to 4 haploid cells. In humans, the haploid cells produced are sperm and egg cells, essential for reproduction to occur. It imporant that meiosis occurs to produce sex cells and not mitosis because the combiation of 2 cells both with the nomral number of chromosomes during fertiliztion would result in an offspring wth double the normal number of chromosomes. Meiosis also created 4 unique haploid cells unlike mitosis which creates identical daughter cells. Meiosis creates new combinations of genetic material in each of the four daughter cells. The gametes produced through meiosis exhibit a larger range of genetic variation and this allows for genetic variation in a population. This genetic variation is increased even more when the two gametes unite during sexual reproduction. This overall helps to increase diversity in a population which increases the chances of the population surviving in a changing environment. Another difference between Meiosis and Mitosis is that Meiosis involves two rounds of nuclear division. The other events of Meiosis are pretty similar to Mitosis but there are some key differences.  Segment 2: More About what meiosis is To begin, a cell will first go through interphase where the cell grows during the G_1 phase, replicates its DNA during the S phase, and prepares for division during the G_2 phase. Then the cell enters Meiosis 1. It begins in prophase 1 where the chromosomes begin to condense. Unlike mitosis, the condensed chromosomes begin to pair up with their homologous partner. The DNA is then broken at the same spot on each chromosome and the homologous chromosomes exchange part of their DNA in a process called crossing over. This process of crossing over increases genetic variation producing unique chromosomes. After crossing over, the spindle fibers capture the chromosomes and move them towards the center of the cell. THis is similar to how the chromosomes in mitosis are moved by spindle fibers, but in meiosis, homologous pairs—not individual chromosomes—line up at the metaphase plate for separation. The orientation of each pair is random and this allows for the formation of gametes with different sets of chromosomes. In anaphase I, the homologues are pulled apart and move apart to opposite ends of the cell. The sister chromatids of each chromosome, however, remain attached to one another and don't come apart. Finally, in telophase I, the chromosomes arrive at opposite poles of the cell and cytokinesis occurs separating the two haploid daughter cells. After meiosis one, the cell does not re enter interphase to grow like it did before meiosis 1. The daughter cells produced by meiosis 1 enter meiosis 2. These cells are haploid but their chromosomes still consist of two sister chromatids. In meiosis II, the sister chromatids separate, making haploid cells with non-duplicated chromosomes. As part of prophase II, chromosomes condense and the nuclear envelope, if it was present, breaks down. The spindle forms between the speratedd centrosomes, and the spindle microtubules begin to capture chromosomes. The two sister chromatids of each chromosome are captured by fibers from opposite spindle poles. In metaphase II, the chromosomes line up individually along the metaphase plate. In anaphase II, the sister...

My AP Biology Thoughts  Unit 5 HeredityWelcome to My AP Biology Thoughts podcast, my name is Pauline Brillouet and I am your host for episode #98 called Unit 5 Heredity: Meiosis and Genetic Diversity. Today we will be discussing how the process of meiosis promotes genetic diversity  Segment 1: Introduction to Meiosis and Genetic DiversityLet's do a quick overview of the stages of meiosis.  The cell must first go through interphase for cell growth, development, and DNA replication. Then, it proceeds to meiosis I where chromosomes condense, the nuclear envelope breaks down, and a synapsis occurs. This synapsis in prophase I involves homologous chromosomes forming a tetrad to line up and cross over at the chiasmata.  The homologous pairs are then split up by the spindles, but sister chromatids remain attached at the centromere. Finally, meiosis II is the exact same process as mitosis except that DNA is not replicated so interphase is shorter. The key component of meiosis II is that now sister chromatids are pulled apart to make four haploid cells.  The purpose of meiosis is to make haploid cells from a diploid cell. It is essential for sexual reproduction in eukaryotes because it produces gametes to be used in fertilization. There are new combinations of genetic material in each of the four gamete cells.  Segment 2: More About Meiosis and Genetic DiversityNow let's explain where genetic diversity comes into play. First, the synapsis in prophase I results in genetic variation because pairs swap genetic information with one another, making recombinant chromosomes. Since the exchange of chromosome segments occurs between non sister chromatids, crossing over creates new combinations of genes in the gametes that are not found in either parent, contributing to genetic diversity. Next, the law of independent assortment explains increased genetic variation. It states that the alleles of two or more different genes get sorted into gametes independently of one another during anaphase I of meiosis. In other words, the allele a gamete receives for one gene does not influence that allele received for another gene. This allows for 2n number of possible chromosome combinations where n is the haploid number of the organism  Lastly, random fertilization extenuates the amount of diploid combinations infinitely. 1 sperm cell has 1 in 8,000,000 possible chromosome combinations, which fuses with an egg cell that also has 1 in 8,000,000 possible chromosome combinations. So there are a total of 64 trillion possible combinations.  Segment 3: Connection to the CourseAs new combinations of gene variants are made, they can make the organism more or less fit or able to survive and reproduce. This ties into natural selection favoring the better adapted organisms Genetic diversity is important because it helps maintain the health of a population, by including alleles that may be valuable in resisting diseases and other stresses. Maintaining diversity gives the population a buffer against change, providing the flexibility to adapt. Extinction risk has been associated with low genetic diversity and several researchers have documented reduced fitness in populations with low genetic diversity.   Thank you for listening to this episode of My AP Biology Thoughts. For more student-ran podcasts and digital content, make sure that you visit http://www.hvspn.com (www.hvspn.com). Thank you! Music Credits: "Ice Flow" Kevin MacLeod (incompetech.com) Licensed under Creative Commons: By Attribution 4.0 License http://creativecommons.org/licenses/by/4.0/ Subscribe to our Podcast https://podcasts.apple.com/us/podcast/my-ap-biology-thoughts/id1549942575 (Apple Podcasts) https://open.spotify.com/show/1nH8Ft9c9f6dmo75V9imCk (Spotify) https://podcasts.google.com/search/my%20ap%20biology%20thoughts (Google Podcasts )   https://www.youtube.com/channel/UC07e_nBHLyc_nyvjF6z-DVg...

My AP Biology Thoughts  Unit 4 Cell Communication and Cell CycleWelcome to My AP Biology Thoughts podcast, my name is Alex Jing and I am your host for episode #96 called Unit 4 Cell Communication and Cell Cycle: Regulation of Cell Cycle. Today we will be discussing How cells regulate their division Segment 1: Introduction to Cell Cycle Regulation The cell cycle includes 4 main stages: G1, S, G2, and mitosis. These phases are responsible for the division of cells. However, how do the cells determine when they can proceed to the next stage of the cell cycle? Cells regulate their advancement in the cell cycle through the use of Cyclin-dependent kinases, or CDKs, and CDK inhibitors. When CDKs are active, they phosphorylate other enzymes in the cell responsible for activating the next stage of the cell cycle. CDK inhibitors are receptors that when activated, will inhibit the CDKs, preventing the cell from going to the next stage.  Segment 2: More About the Regulation of the Cell Cycle A prominent example of why CDKs and their inhibitors are so important is the development of cancer. Cancers form when cells are growing at an rapid, unrestricted rate, and are usually caused by some mutations in the cell which results in either overactive CDKs or inactive CDK inhibitors. P53 is a CDK inhibitor which is responsible for ensuring that DNA is not damaged during the replication process. If it detects damaged DNA it will send out signals to inhibit the CDKs. If a mutation caused the P53 to not be responsive, than cells could be able to divide with damaged DNA, leading to a new cancer to form. Segment 3: Connection to the Course Regulation of the cell cycle is an essential part of all living organisms. Being able to conduct mitosis is what allows organisms to grow and replace damaged cells, and being able to regulate this process is extremely important to ensuring that division is done correctly.  Thank you for listening to this episode of My AP Biology Thoughts. For more student-ran podcasts and digital content, make sure that you visit http://www.hvspn.com (www.hvspn.com).   Music Credits: "Ice Flow" Kevin MacLeod (incompetech.com) Licensed under Creative Commons: By Attribution 4.0 License http://creativecommons.org/licenses/by/4.0/ Subscribe to our Podcast https://podcasts.apple.com/us/podcast/my-ap-biology-thoughts/id1549942575 (Apple Podcasts) https://open.spotify.com/show/1nH8Ft9c9f6dmo75V9imCk (Spotify) https://podcasts.google.com/search/my%20ap%20biology%20thoughts (Google Podcasts )   https://www.youtube.com/channel/UC07e_nBHLyc_nyvjF6z-DVg (YouTube)  Connect with us on Social Media Twitterhttps://twitter.com/thehvspn ( @thehvspn)

My AP Biology Thoughts  Unit 3 Cellular EnergeticsWelcome to My AP Biology Thoughts podcast, my name is Adrienne Li and I am your host for episode #76 called Unit 3 Cellular Energetics: Anaerobic Respiration. Today we will be discussing what anaerobic respiration is, the two types, examples, and its connection to the rest of unit 3.  Segment 1: Introduction to Anaerobic RespirationTo start off, let me define what anaerobic respiration is. It is the process that regenerates NAD+ for glycolysis so it can produce ATP and its key characteristic is that it occurs when oxygen is not available. This distinguishes anaerobic from aerobic respiration, which occurs when oxygen is available. Also, it's important to stress that its main purpose is to regenerate NAD+ which is a big misconception that many people have.  Segment 2: More About Anaerobic RespirationDiving deeper into anaerobic respiration, there are two types. One is alcohol fermentation which occurs in plants, fungi, and bacteria. It starts out with glycolysis where glucose is converted into pyruvate, but since oxygen is not present, it converts into CO2 and acetaldehyde. Then, energy from NADH is applied to acetaldehyde and converts into ethanol and NAD+, thus regenerating the NAD+ that is necessary for glycolysis to occur and produce 2 ATP. A real life example is seen in yeast, where they use alcoholic fermentation which allows bread dough to rise. This is because CO2 is a waste product of alcoholic fermentation which causes gas bubbles to form. The other type of anaerobic respiration is lactic acid fermentation which occurs in animals. Similar to alcohol fermentation, it uses glucose to create pyruvate but then it is converted to lactate instead of acetaldehyde and lactic acid is produced instead of CO2. During this process, NADH is oxidized into NAD+ which is used in glycolysis to produce 2 ATP. This occurs when we exercise which we feel through the burning sensation during a tough workout. The burning sensation is lactic acid build up, which occurs when our respiratory and cardiovascular systems cannot transport oxygen to our muscles fast enough. Therefore, they resort to lactic acid fermentation to immediately produce ATP. Segment 3: Connection to the CourseTo connect anaerobic respiration to the rest of the unit, let's zoom out a bit to the bigger picture of cellular energetics. Keep in mind, anaerobic respiration does produce energy, that's just not its main purpose. With the regeneration of NAD+, it is used in glycolysis to produce 2 ATP. Other cellular pathways that exist include the krebs cycle and chemiosmosis, however they don't occur in anaerobic respiration because oxygen isn't present. They do however occur in aerobic respiration because oxygen is present and acts as the final electron acceptor. This aids in the formation of a proton gradient along with the energy of the electrons from NADH and FADH2 which actively transports H+ into the intermembrane space. From there, chemiosmosis occurs where H+ flows from high to low concentration and back into the matrix through ATP synthase, which then creates ATP. This is a brief explanation of aerobic respiration but it shows the different processes that occur in both due to the presence or absence of the final electron acceptor oxygen. So that about sums up anaerobic respiration and its connection to other cellular energetic pathways.  Thank you for listening to this episode of My AP Biology Thoughts. For more student-ran podcasts and digital content, make sure that you visit http://www.hvspn.com (www.hvspn.com). See you next time bio buddies! Music Credits: "Ice Flow" Kevin MacLeod (incompetech.com) Licensed under Creative Commons: By Attribution 4.0 License http://creativecommons.org/licenses/by/4.0/ Subscribe to our Podcast https://podcasts.apple.com/us/podcast/my-ap-biology-thoughts/id1549942575 (Apple Podcasts) https://open.spotify.com/show/1nH8Ft9c9f6dmo75V9imCk...

My AP Biology Thoughts  Unit 3 Cellular EnergeticsWelcome to My AP Biology Thoughts podcast, my name is Helena Holley and I am your host for episode #78 called Unit 3 Cellular Energetics: Light Dependent Reactions. Today we will be discussing the mechanisms of the first stage of photosynthesis known as the light dependent reactions or non-cyclic photophosphorylation.  Segment 1: Introduction to Light Dependent ReactionsThe light dependent reactions is a process in which light energy is converted to chemical energy. In plants, this reaction takes place in thylakoid membranes of chloroplasts. The process involves the use of two photosystems called photosystem I and II. These are embedded in the membrane and they contain many pigments which optimize them for harvesting light. The process involved the use of an electron transport chain to create a proton gradient which is used to make ATP and NADH.  Segment 2: More About Light Dependent ReactionsNow that you have an overview of the light dependent reactions, I'll take you through the process step by step. The reactions begin when photosystem II absorbs light causing an electron to be boosted to a higher level. This electron is passed to an acceptor molecule and it is replaced by an electron from water, which causes h20 to split into ½ O2 and 2 H+ molecules. The O2 released is the oxygen we breathe. The high energy electron that is energized by the light is passed down an electron transport chain. The electron releases energy as it travels through the chain which drives the pumping of H+ from the stroma into the thylakoid lumen, building a gradient. Since this proton gradient is created, the H+ ions will naturally want to flow down it. In order to flow down their gradient back into the stroma, they have to go through the ATP synthase enzyme. This creates ATP from ADP and Pi through chemiosmosis. One of the last locations of the electrons in their electron chain is photosystem I where the electron is boosted to an even higher energy level and transferred to an acceptor molecule. This high energy electron travels down a short final leg of the electron transport chain and at the end it is passed to NADP+ resulting in the creation of NADPH.  Segment 3: Connection to the CourseThe light dependent reactions are a significant part of the process of photosynthesis. The ATP and NADPH created in the light dependent reactions is used to power the production of carbohydrates from carbon dioxide. Carbohydrates are a main food source for organisms and are essential for survival. Without light dependent reactions, photosynthesis cannot occur and energy for the photosynthetic organisms would not be created. This would result in the organism dieing. The light dependent reactions are essential to the organisms survival. Enzymes are also a key component of light dependent reactions such as the ATP synthase enzyme. As discussed in the course, enzymes require certain conditions in order to function and their functioning is important to the light dependent reactions.  Thank you for listening to this episode of My AP Biology Thoughts. For more student-ran podcasts and digital content, make sure that you visit http://www.hvspn.com (www.hvspn.com). Keep your plants in the sun! Music Credits: "Ice Flow" Kevin MacLeod (incompetech.com) Licensed under Creative Commons: By Attribution 4.0 License http://creativecommons.org/licenses/by/4.0/ Subscribe to our Podcast https://podcasts.apple.com/us/podcast/my-ap-biology-thoughts/id1549942575 (Apple Podcasts) https://open.spotify.com/show/1nH8Ft9c9f6dmo75V9imCk (Spotify) https://podcasts.google.com/search/my%20ap%20biology%20thoughts (Google Podcasts )   https://www.youtube.com/channel/UC07e_nBHLyc_nyvjF6z-DVg (YouTube)  Connect with us on Social Media Twitterhttps://twitter.com/thehvspn ( @thehvspn)

My AP Biology Thoughts  Unit 3 Cellular EnergeticsWelcome to My AP Biology Thoughts podcast, my name is Pauline Brillouet and I am your host for episode #73 called Unit 3 Cellular Energetics: Pyruvate Oxidation. Today we will be discussing the details and significance of this step of cellular respiration. Segment 1: Introduction to pyruvate oxidation Pyruvate oxidation is the second step in cellular respiration. It is often called the link reaction because it bridges glycolysis to the krebs cycle. The process takes place in the mitochondrial matrix of eukaryotes. The reactants are pyruvate and CoA, and the products are carbon dioxide and acetate. It's whole purpose is to further oxidize the original glucose molecule that how now split into two pyruvate molecules Segment 2: More About pyruvate oxidation Pyruvate is a 3 carbon sugar left over from glycolysis. A carboxyl group is removed from pyruvate, releasing carbon dioxide and leaving it as a 2 carbon sugar. Pyruvate was therefore essentially oxidized and lost electrons. These lost electrons are then used to reduce NAD+ to NADH, so NAD+ is gaining an electron. The 2 carbon sugar now called acetate then binds to coenzyme A (CoA) to form acetyl CoA. Segment 3: Connection to the Course The process of pyruvate oxidation is essential because of its products. The carbon dioxide that is released is then able to be ingested by plants so that they can perform photosynthesis. The acetyl CoA produced is needed to kick start the next step in cellular respiration called the krebs cycle. Finally, the reduction of NAD+ to NADH is very important because NADH is now an electron carrier that will get oxidized later in the electron transport system. The oxidation of NADH allows for a proton gradient across the inner mitochondrial membrane to diffuse back through the ATP synthase. This process is also helpful to help visualize redox reactions, where reduction must happen with oxidation and vice versa. NAD+ is only able to be reduced because the pyruvate was oxidized. Overall, glucose is simply being further oxidized in this link reaction to ultimately produce ATP for cell work and functioning.  Thank you for listening to this episode of My AP Biology Thoughts. For more student-ran podcasts and digital content, make sure that you visit http://www.hvspn.com (www.hvspn.com).  Music Credits: "Ice Flow" Kevin MacLeod (incompetech.com) Licensed under Creative Commons: By Attribution 4.0 License http://creativecommons.org/licenses/by/4.0/ Subscribe to our Podcast https://podcasts.apple.com/us/podcast/my-ap-biology-thoughts/id1549942575 (Apple Podcasts) https://open.spotify.com/show/1nH8Ft9c9f6dmo75V9imCk (Spotify) https://podcasts.google.com/search/my%20ap%20biology%20thoughts (Google Podcasts )   https://www.youtube.com/channel/UC07e_nBHLyc_nyvjF6z-DVg (YouTube)   Connect with us on Social Media Twitterhttps://twitter.com/thehvspn ( @thehvspn)

My AP Biology Thoughts  Unit 3 Cellular EnergeticsWelcome to My AP Biology Thoughts podcast, my name is Saarim Rizavi and I am your host for episode #79 called Unit 3 Cellular Energetics: The Calvin Cycle. Today we will be discussing the second stage of photosynthesis known as the Calvin Cycle (or the light-independent reactions). We will be talking about what the calvin cycle is in the first place and I will give a brief overview of the whole process. Then, I will go into the specific reactions of the calvin cycle and the three main steps of the calvin cycle which include carbon fixation, reduction, and regeneration. Finally, to end it off, I will place and discuss the calvin cycle in the scope of the broader topic of cellular energetics and just the overall importance of the calvin cycle to the environment. Before I begin, I would like to give credit to a couple of websites and resources that were used to create this podcast which include sciencing.com, national geographic, khan academy, biology libretexts, and Ms. Ribecca's AP Biology Cellular Energetics Videos. So thank you to them for making this podcast possible.  Segment 1: Introduction to The Calvin Cycle Calvin cycle is named Calvin cycle because it was named after Melvin C. Calvin who discovered it and won a Nobel Prize in Chemistry for it What is the Calvin Cycle?  A process that plants and algae use to turn carbon dioxide from the air into sugar (glucose) Every living thing on Earth depends on the Calvin cycle either directly or indirectly to survive The calvin cycle takes place in the stroma - the inner space of the chloroplasts Function - to create three carbon sugars which can be used to build other sugars such as glucose, starch, and cellulose that is then used by plants to function and survive Steps of Calvin Cycle (quick overview) Carbon fixation - organic carbon in the form of carbon dioxide in the air is incorporated into organic molecules Inorganic carbon converted to organic compounds by living organisms Reduction - the organic molecules produced in the first stage accept electrons and are reduced  Regeneration - the reduced organic molecules use energy from ATP to make RuBP to start the cycle all over again Cycle is powered by ATP and NADPH from light dependent reactions Segment 2: More About The Calvin Cycle“Preliminary step”  In plants, carbon dioxide enters the leaves through the stomata, which is located on the underside of plant leaves The CO2 diffuses through intercellular space until it reaches the mesophyll cells - CO2 then diffuses into the stroma of the chloroplast  Stroma - besides the CO2, there's an enzyme called rubisco and three molecules of ribulose bisphosphate (RuBP) - RuBP = 5 carbon acceptor molecule Carbon Fixation A reaction between carbon dioxide and RUBP occurs and produces a 6 carbon compound that splits into 2 molecules of a three carbon compound known as 3-PGA, which has 3 carbons and one phosphate 3 molecules of carbon dioxide react with 3 molecules of RuBP to produce 6 molecules of the 3 carbon molecules, 3-PGA - reaction catalyzed by rubisco A turn of the calvin cycle involves only 1 RuBP and 1 carbon dioxide molecule forming 2 molecules of 3-PGA - it takes 3 turns of the calvin cycle to produce 6 molecules of 3-PGA Reduction The 3-PGA molecules created through fixation are converted into molecules of simple sugar, known as G3P The 6 molecules of 3 PGA use 6 molecules of ATP and 6 molecules of NADPH, which store the light reactions, to generate 6 molecules of G3P, a 3 carbon sugar Reduction reaction because the 3-PGA molecules gain electrons - the PGA is basically reduced to G3P ATP - energy is released with the loss of the terminal phosphate group converting it to ADP  NADPH - both energy and a hydrogen atom are lost, converting it into NADP+; NADPH donates electron to a 3 carbon intermediate to make G3P One turn of the calvin cycle would

My AP Biology Thoughts  Unit 3 Cellular EnergeticsWelcome to My AP Biology Thoughts podcast, my name is Jacqueline Sun and I am your host for episode #5 called Unit 3 Cellular Energetics: OXIDATIVE PHOSPHORYLATION. Today we will be discussing the formation of ATP in the vital final step of cellular respiration.  Segment 1: Introduction to Oxidative Phosphorylation Oxidative Phosphorylation is the name for the entire final process in which ATP is created; it can be split into two parts which are the ETC and chemiosmosis.  Is an aerobic process which requires oxygen and follows the Krebs cycle. Uses 3 NADH and 1 FADH2 produced from the Krebs cycle, also requires oxygen as the final electron acceptor. The final product of Oxidative Phosphorylation is, of course, ATP. A byproduct is H2O. Takes place in the inner membrane of the mitochondria, involves 4 protein complexes labeled with roman numerals 1-4 from left to right and an ATP synthase that are all embedded within the membrane. Segment 2: More About Oxidative PhosphorylationETC There are two electron carriers which will start the ETC: NADH and FADH2. I will first talk about NADH, because the process for FADH2 is slightly different. The electron carrier NADH is oxidized into NAD+, losing two electrons which are pumped into protein I. This energy transfer allows one H+ ion (lost from the NADH) to be actively transported into the intermembrane space. The H+ must be actively transported because there is a higher concentration of H+ in the intermembrane space than in the matrix. The electrons are then transferred by a transfer protein to protein III , and the energy that is lost in the transfer is again used to pump an H+ ion into the intermembrane space. Finally the lower-energy level electrons are transported once more to protein IV, and the energy lost in the transfer is used to pump another H+ over. At this point, the 2 electrons are much lower in energy level and must be removed to prevent a backup of electrons, so they will exit the last protein complex and bind with two free-flowing H+ ions and ½ of an O2 molecule to create H2O. This is how oxygen acts as the final electron acceptor and how it contributes to the creation of the byproduct of H2O. In summary, by the end of the process, NADH has pumped 3 total electrons. Now let's talk about FADH2. FADH2 is the other electron carrier and is oxidized at protein II, losing two electrons to be pumped into the ETC and turning into FAD and two H+ ions. It will then follow the same process as NADH. The key difference here is that FADH2 starts at protein II while NADH starts at protein I, meaning FADH2 will only pump two protons, making it slightly less efficient than NADH.  Chemiosmosis (compared to previous process, considerably more straightforward) Overall, ATP synthase, the central protein complex of chemiosmosis, will convert the potential energy of the proton gradient into chemical energy in ATP. Due to the ETC, there is a higher concentration of protons in the intermembrane space and lower conc. in the matrix, the protons in the higher conc. will naturally want to move down their electrochemical gradient into the matrix. The H+ ions will pass through the ATP synthase back into the matrix. The energy derived from the movement of these protons down their gradient and through the ATP synthase allows for phosphorylation, or the binding of Phosphate to ADP, to occur. From this, we have finally created ATP, and the cycle of cellular respiration is complete. Segment 3: Connection to the Course Oxidative Phosphorylation is extremely important, for it is the last component of cellular respiration, one of the most important life functions that generates an organism's energy in the form of ATP. Without this energy, I would not be speaking here right now, and all life in general would cease. Large quantities of ATP cannot be created without this process, but at the same time Oxidative

My AP Biology Thoughts  Unit 4 Cell Communication and Cell CycleWelcome to My AP Biology Thoughts podcast, my name is Pauline Brillouet and I am your host for episode #87 called Unit 4 Cell Communication and Cell Cycle: Reception: Ligand Gated Ion Channels and Intracellular Receptors. Today we will be discussing the function and examples of these two types of receptors. Segment 1: Introduction to Reception: Ligand Gated Ion Channels and Intracellular ReceptorsLigand gated ion channels and intracellular receptors are both involved in the first step of a signaling pathway known as reception. Reception is the process where a signal, or otherwise called a ligand, binds to a receptor. The ligand-binding domain of the receptor recognizes the specific chemical messenger to then start transduction. One thing to note is that the binding of ligand and receptor is noncovalent, so it is temporary and functions like an enzyme-substrate complex where size and shape of the signal is essential.  The main difference between the two receptors we are exploring is their location. Ligand-gated ion channels are membrane proteins. Meaning they are embedded in the membrane. Like the name suggests, intracellular receptors obviously lie within the cell.  Segment 2: More About Reception: Ligand Gated Ion Channels and Intracellular ReceptorsLigand gated ion channels either open or close in response to binding. They conduct ion flow. An example is a neurotransmitter binding to neurons, which opens the gate for Na+ Intracellular receptors require ligands that are small or nonpolar because they can diffuse through the membrane. An example of this is the sex hormone estrogen or any steroid hormone. When a hormone enters a cell and binds to its receptor, it causes the receptor to change shape, allowing the receptor-hormone complex to enter the nucleus (if it wasn't there already) and regulate gene activity Segment 3: Connection to the CourseThe hydrophilic ion channel lets ions cross the membrane without having to touch the hydrophobic core of the https://www.khanacademy.org/science/biology/membranes-and-transport/the-plasma-membrane/a/structure-of-the-plasma-membrane (phospholipid bilayer). Changes in ion levels inside the cell can change the activity of other molecules, such as ion-binding enzymes. The binding of neurotransmitters to neurons is also essential for the entire nervous system and basic brain functions such as attention, learning, and memory.  Intracellular receptors are unique because they cause these changes very directly, binding to the DNA and altering transcription themselves. A very important gas that acts as a ligand that is able to directly diffuse through the membrane is Nitric oxide (NO). It activates a signaling pathway in the smooth muscle surrounding blood vessels, one that makes the muscle relax and allows the blood vessels to expand. Drugs that treat heart diseases release NO to bind to the intracellular receptors and dilate vessels to restore blood flow to the heart. Thank you for listening to this episode of My AP Biology Thoughts. For more student-ran podcasts and digital content, make sure that you visit http://www.hvspn.com (www.hvspn.com). Thank you! Music Credits: "Ice Flow" Kevin MacLeod (incompetech.com) Licensed under Creative Commons: By Attribution 4.0 License http://creativecommons.org/licenses/by/4.0/ Subscribe to our Podcast https://podcasts.apple.com/us/podcast/my-ap-biology-thoughts/id1549942575 (Apple Podcasts) https://open.spotify.com/show/1nH8Ft9c9f6dmo75V9imCk (Spotify) https://podcasts.google.com/search/my%20ap%20biology%20thoughts (Google Podcasts )   https://www.youtube.com/channel/UC07e_nBHLyc_nyvjF6z-DVg (YouTube)   Connect with us on Social Media Twitterhttps://twitter.com/thehvspn ( @thehvspn)

My AP Biology ThoughtsUnit 3 Episode #74 Krebs CycleWelcome to My AP Biology Thoughts podcast, my name is Corrinna and I am your host for episode 74 called Unit 3 cell energetics: the Krebs Cycle. Today we will be discussing the Krebs Cycle.  Segment 1: Defining The Krebs CycleThe Krebs cycle, also known as the citric acid cycle, is the third step in cellular respiration, the process by which organisms combine oxygen and other molecules into energy that is used in life-sustaining activities. Before the Krebs cycle, glycolysis and pyruvate oxidation occur.  The Krebs cycle occurs in the mitochondrial matrix in eukaryotes. The matrix of the mitochondria is the part of the mitochondria inside the inner membrane. This process occurs twice for every glucose molecule that goes through glycolysis. The Krebs cycle is a very detailed process.  First, acetyl coenzyme A, which was produced in the previous step of cellular respiration, combines with oxaloacetate to form citrate. This molecule is converted to its isomer, which is then oxidized and releases carbon dioxide. During this process, NAD+ is reduced to form NADH. Next, another molecule is oxidized and NAD+ is again reduced to NADH, and a molecule of carbon dioxide is released. THe coenzyme A of succinyl coensyme A is replaced by a phosphate group which is transferred to ADP to produce ATP, or in some cases, GDP. A four carbon molecule called succinate is also produced. Next, succinate is oxidized and FAD is reduced to FADH2. Water is then added to the resulting molecule, and another molecule of NAD+ is reduced to NADH. 2 Oxaloacetate is also produced which allows the cycle to start again.  Those are the very detailed steps of the Krebs cycle, but the most important part to remember is the energy transfers that occur and what the krebs cycle produces. In the Krebs cycle NAD+ is reduced to NADH, and FAD is reduced to FADH2. ADP and phosphate are combined to produce ATP. Citrate is oxidized, and heat is lost in the process. In the end, the krebs cycle produces 4 CO2, 2 ATP, 6 NADH, and 2 FADH2. Carbon dioxide is the waste product and is moved into the blood, and acetyl coa is used to convey the carbon atoms to the cycle.  Segment 2: Examples of the Krebs CycleThe Krebs cycle is important because it produces molecules that are required for cellular respiration, which enables organisms to create energy that they need to function. The Krebs cycle occurs in all organisms that undergo cellular respiration. It happens in an aerobic environment.  Segment 3: Digging Deeper into the Krebs CycleThe Krebs cycle also supports the endosymbiotic theory. Prokaryotes go through the Krebs cycle in the cytoplasm. One main aspect of the endosymbiotic theory is that mitochondria used to be prokaryotic cells, but were absorbed by larger cells to form eukaryotic cells with membrane bound organelles. Since eukaryotic cells go through the krebs cycle in the mitochondria, this supports the endosymbiotic theory.  Thank you for listening to this episode of My AP Biology Thoughts. For more student-run podcasts, make sure that you visit http://www.hvspn.com (www.hvspn.com). See you next time on My AP Biology thoughts podcast! Music Credits: "Ice Flow" Kevin MacLeod (incompetech.com) Licensed under Creative Commons: By Attribution 4.0 License http://creativecommons.org/licenses/by/4.0/ Subscribe to our Podcast https://podcasts.apple.com/us/podcast/my-ap-biology-thoughts/id1549942575 (Apple Podcasts) https://open.spotify.com/show/1nH8Ft9c9f6dmo75V9imCk (Spotify) https://podcasts.google.com/search/my%20ap%20biology%20thoughts (Google Podcasts )   https://www.youtube.com/channel/UC07e_nBHLyc_nyvjF6z-DVg (YouTube)   Connect with us on Social Media Twitterhttps://twitter.com/thehvspn ( @thehvspn)

My AP Biology ThoughtsUnit 4 Cell Communication and Cell CycleWelcome to My AP Biology Thoughts podcast, my name is Nikki Evich and I am your host for episode #82 called Unit 4 Cell Communication and Cell Cycle: Intro to Signaling Transduction Pathway. Today we will be discussing the components that make up a pathway. Segment 1: Introduction to the signaling transduction pathway● Signal also call ligand binds to a receptor on target cell membrane ○ , starts the pathway, ○ had to fit receptor, ○ once bound, transduction is initiated ● Receptor- intracellular or extracellular ○ Binding domain recognizes specific chemical messengers ● transduction-lots of varian with transduction ○ Could activate inactive protein by phosphorylating ○ Amplifies with secondary messengers ● Response- what the end result is ○ Can be short or long ○ Activate enzyme or move cell-short ○ Alter gene expression levels or cell division (apoptosis)-long Segment 2: More About the signaling transduction pathway● Type 1 ● Once the food is broken down into glucose, these molecules are then absorbed into the bloodstream. The high glucose levels in the bloodstream activate the beta cells in the pancreas to start producing insulin. Insulin is a hormone created in the pancreas. In the pancreas, beta cells are present which are in charge of secreting the insulin into the bloodstream once they detect an increase in blood glucose. Insulin travels to three main destinations-muscle, fat, and liver cells. ● This is where the transduction pathway happens ● The insulin will then bind to the insulin receptors. The insulin receptors are made up of extracellular alpha subunits and transmembrane beta subunits. ● When the insulin binds to the extracellular alpha subunits, the beta subunits become activated and auto phosphorylate. This means that they phosphorylate themselves. ● This leads to the phosphorylation and activation of the IRS protein. The IRS protein is regulated and can be phosphorylated by PTEN. PTEN can regulate phosphorylation and activate IRS Isaforms by dephosphorylating IRS. Once IRS is activated, proteins including PI3K will bind to the IRS protein through their P85 subunit. ● The PI3K will then phosphorylate PIP2 to PIP3. When the PIP3 concentration increases, other proteins like PDK1 and AKT are recruited towards the plasma membrane. PIP3 activates PDK1 which then phosphorylates AKT. ● Cells have reservoirs of intracellular vesicles that contain GLUT4, a glucose transporter. So in order for glucose to be let into the cell the glucose transporters have to translocate to the plasma membrane. However, AS160 inhibits this process. ● Luckily, phosphorylated AKT inactivates AS160. So when AKT is phosphorylated by PDK1, AS160 is inactivated which in turn allows for the translocation of glut 4 so it can embed itself in the membrane. Now glucose can get into the cell for storage and other purposes. Segment 3: Connection to the Course● Involved in evolution-some cell transduction pathways stayed the same ○ Track common ancestors Interruptions in this pathway are serious like with the brain sending signals out ● Involved in negative feedback loops and homeostasis ● Body is constantly sending signals, though it may seem minute it makes you be able to do all you do ● In all walks of life ● Can be seen in all types of diseases and illness from Diabetes to cancer Thank you for listening to this episode of My AP Biology Thoughts. For more student-ran podcasts and digital content, make sure that you visit www.hvspn.com. Bye now! Music Credits: ● "Ice Flow" Kevin MacLeod (incompetech.com) ● Licensed under Creative Commons: By Attribution 4.0 License ● http://creativecommons.org/licenses/by/4.0/ Subscribe to our Podcast https://podcasts.apple.com/us/podcast/my-ap-biology-thoughts/id1549942575 (Apple Podcasts) https://open.spotify.com/show/1nH8Ft9c9f6dmo75V9imCk (Spotify)...

My AP Biology Thoughts  Unit 4 Cell Communication and Cell CycleWelcome to My AP Biology Thoughts podcast, my name is Chloe McGregor and I am your host for episode #93 called Unit 4 Cell Communication and Cell Cycle: The Cell Cycle. Today we will be discussing the basics of the cell cycle including how it works and what products are made.  Segment 1: Introduction to the Cell CycleThe cell cycle is split up into 2 different parts, each with their own purpose. The first part of the cell cycle is called interphase. The cell spends a majority of its time in this phase. Interphase itself is made up of 3 different stages. These stages are the G1, S, and G2 phase. The first step in interphase is G1. During this step, the cell spends its time growing in size and gaining a sufficient amount of resources. With this abundance of resources, the cell is able to replicate its DNA and intracellular components during the S phase. The third step is G2 where the cell continues its growth and will stop its progression to the mitotic phase if there are any issues or damaged DNA. The second part of the cell cycle is the mitotic phase which has 2 parts. The first part is mitosis. Mitosis consists of four steps: Prophase, metaphase, anaphase, and telophase. More details about these steps will be discussed later in the episode, but generally they work together in order to separate the replicated DNA. The second part of the mitotic phase is cytokinesis where the cell actually splits into 2 new identical daughter cells. Overall, each step in the cell cycle is important to grow the cell and its resources in order to produce 2 identical daughter cells, each with the same copies of DNA. Another important part of the cell cycle is the G0 phase. Although this isn't the generic path of cell replication , a cell may enter the G0 phase if there is a non sufficient amount of resources and nutrients available to proceed to healthy replication. Cells may also enter G0 if they are adult cells that are not necessarily looking to replicate. For example, a lot of cells in your brain and nervous system stop replicating once you reach adulthood, so an injury in these areas could be extremely difficult, or impossible, to heal. Segment 2: More About the Cell CycleTo go more in depth, let's talk about the different steps in mitosis. Once again, these steps are prophase, metaphase, anaphase, and telophase. The goal of mitosis is to separate the replicated DNA on opposite sides of the cell, with both sides having identical copies of the DNA. Prophase begins once G2 is finished and the cell has grown enough. In prophase, the DNA condenses, and the replicated chromosomes have a more visible shape to them. The replicated chromosomes are called sister chromatids and are linked together at a point called the centromere. The next step, metaphase, is when the replicated chromosomes line up in the center of the cell in a line. Anaphase is next, and this is where the spindle fibers on each side of the cell attach to the centromere region on each sister chromatid. Then, the fibers pull the sister chromatids apart, leaving opposite sides of the cell with identical genetic material. Telophase is the last stage of mitosis where each side of the cell begins to form a nuclear envelope around the new genetic material. The chromosomes also unravel back into chromatin. Once mitosis is complete, the cell membrane scrunches in the middle of the cell causing it to physically separate into two identical daughter cells. This step is called cytokinesis. Another important point to touch on is the checkpoints that occur during the cell cycle. Although there is a separate episode on cell cycle regulation, it is important to understand that the cell reaches checkpoints throughout the entire cell cycle which ensure that it is healthy, and that the DNA is replicating correctly. There are 3 checkpoints. These are near the end of G1, between G2 and the M phase, and one...

My AP Biology Thoughts  Unit 4 Cell Communication and Cell CycleWelcome to My AP Biology Thoughts podcast, my name is CJ and I am your host for episode 92 called Unit 4 Cell Communication and Cell Cycle: Feedback loops. Today we will be discussing how organisms maintain homeostasis Segment 1: Introduction to Feedback loops There are 2 types of feedback loops found in the systems of our bodies. The first is negative and the second is positive. These feedback loops are ways for our body to determine whether the cells are healthy or sickly. These feedback loops typically occur when the product or output of an event or reaction changes the organism's response to that reaction. So typically, the cells in our body do not want anything to change, they have to have optimal temperature, pH, concentration, everything. The process of regulating these happen during feedback loops and different stimuli and reactions occur to perform this. Looking at the different types of feedback loops, we can see that both try to maintain homeostasis. They both have an overarching goal of consistency and equilibrium.  Segment 2: More About Feedback loops Negative feedback loops are typically the most popular and common example of feedback loops. This is when a stimulus disrupts a receptor. This receptor then in turn puts out various tasks to help alleviate the stimulus until it is all gone. A great example of this is the thermostat in a house. The stimulus is the temperature getting too cold. This negative feedback in turn activates the thermostat which turns on the heat. And until the temperature in the room matches the temperature on the thermostat, the heat continues to warm up the room. Now for the opposite; a positive feedback loop. This is just a series of different reactions that cycles until a big event occurs at the end of it. The best way to look at these different types of feedback loops is to look at the graphs that represent them. On the X-axis is time while the y-axis is stimulus. The cell wants to be at 0, which means homeostasis. Now for negative feedback loops, we see that the line starts at 0 but then an event occurs that throws off the balance. Either going up or down, the cell corrects it and heads towards 0, however it overshoots and continues the pattern of a sine graph until its amplitude slowly reaches 0. Positive feedback loops are a bit different. In terms that the graph slowly goes up and up until it reaches the even and then plummets back to 0. These graphs help us visualize the process and the final goal of each loop. Segment 3: Connection to the Course This all plays into the theme of systems in biology. Systems in our bodies run all around the clock to maintain homeostasis and to keep us healthy and strong. These feedback loops are necessary to tell the cell whether something is wrong or right, and this is what causes these loops. It is important to know this because these types of activities ties into everyday things. Just like thermostats and pregnancies. It is important to know and understand these things so we know when something goes wrong. It's also important to note that our bodies are functioning the right way and it's constant need to keep us healthy. Thank you for listening to this episode of My AP Biology Thoughts. For more student-ran podcasts and digital content, make sure that you visit http://www.hvspn.com (www.hvspn.com).  Music Credits: "Ice Flow" Kevin MacLeod (incompetech.com) Licensed under Creative Commons: By Attribution 4.0 License http://creativecommons.org/licenses/by/4.0/ Subscribe to our Podcast https://podcasts.apple.com/us/podcast/my-ap-biology-thoughts/id1549942575 (Apple Podcasts) https://open.spotify.com/show/1nH8Ft9c9f6dmo75V9imCk (Spotify) https://podcasts.google.com/search/my%20ap%20biology%20thoughts (Google Podcasts )   https://www.youtube.com/channel/UC07e_nBHLyc_nyvjF6z-DVg (YouTube)  Connect with us on...

My AP Biology Thoughts  Unit 4 Cell Communication and Cell CycleWelcome to My AP Biology Thoughts podcast, my name is Morgan and I am your host for episode #89 called Unit 4 Cell Communication and Cell Cycle: transduction; secondary receptors. Today we will be discussing secondary receptors and their role in the signal transduction Segment 1: Introduction to transduction pathwaysIn signal transduction, there are three things that are necessary for the cell to do.  First, the signal, or ligand, must bind to the receptor, either on the cell's surface or inside the membrane. This is the first component, which is known as reception.  From there, the transduction occurs, where proteins are activated, and it is the component that includes secondary messengers.  Lastly, the transduction pathway eventually elicits a response from the cell, which is the overall goal of cell signaling. This response can be anything from activating an enzyme to initiating apoptosis, which is programmed cell death.  After the ligand binds to its receptor and changes the shape, the cell sets off with a series of signaling events, all designed to amplify the signal and eventually reach a response. This chain of events is what we call the transduction pathway. The first way transduction occurs is through protein phosphorylation, where a series of proteins are activated by phosphorylases. The other way transduction can occur is by secondary messengers, so let's learn more about those! Segment 2: More About secondary messengersSecondary messengers are small molecules that are specifically not proteins, although proteins play a huge role in the cell cycle. These secondary messengers are the ones that receive the signal from the first ligand when it binds to its receptor. The signal, or ligand, is thought of as the first messenger, so these little molecules that pick up and carry along the signal are therefore secondary messengers. Two examples of secondary messengers are calcium ions and cyclic AMP. First, calcium in the form of Ca2+ ions are a very common secondary messenger in cells. They are stored in the endoplasmic reticulum, which is purposeful so they are isolated from the rest of the cell until they are needed and released. The pathway starts with a signal that binds to and opens one of the ligand-gated calcium ion channels in the cell. With an open ion channel, calcium ions from the extracellular space are able to flow freely into the cell and greatly increase the concentration of Ca2+ ions in the cytoplasm. From there, the abundance of calcium ions bind with various proteins in the cell, changing their shape and function to initiate a response. Secondary messengers are nonspecific, so the signals can lead to many types of responses based on the proteins present and type of cell. The next example of a secondary messenger is cyclic AMP. Cyclic AMP is made when an enzyme gets a specific signal and converts ATP into the new molecule of cyclic AMP, also referred to as cAMP. Once it is made from the ATP, cAMP activates protein kinase A, a molecule that phosphorylates other proteins and passes along the signal to produce different responses. Segment 3: Connection to the CourseSecondary messengers have many connections to this unit of cell communication and the cell cycle, as well as the overall biology course. To start, it is important to understand signal transduction pathways and the three components before diving deeper into secondary messengers. We must know the purpose of these signaling pathways, as well as how they are started and what happens, which would be our three components of reception, transduction, and response. Additionally, we know that the purpose of secondary messengers is to amplify a signal and achieve a response, which we can see physically by responses in our body. For example, one of the secondary messengers we talked about earlier was calcium, which has a specific signaling pathway in...

My AP Biology Thoughts  Unit 4 Cell Communication and Cell CycleWelcome to My AP Biology Thoughts podcast, my name is Helena Holley and I am your host for episode #91 called Unit 4 Cell Communication and Cell Cycle: Changes in signal transduction pathways. Today we will be discussing factors that affect signal transduction pathways and their consequences in the body.  Segment 1: Introduction to Changes in signal transduction pathwaysThe first thing to know is what are signal transduction pathways? This is a process in which extracellular ligands/signaling molecules bind to receptors, which could be located inside the cell or on it's surface, and triggers a series of events which results in a cellular response or multiple responses. Depending on the pathway this process could involve the use of a secondary messenger. This is typically an intracellular signaling molecule that amplifies the signal inside the cell in response to the presence of an extracellular signaling molecule in order to reach the target cell that will initiate cellular response. The signal transduction pathways can alter a lot of cell functions and that is why it is critical that all parts of the process function correctly. Changes in parts of the process can cause disorders and disease.  Segment 2: More About changes in signaling transduction pathwaysThe signaling transduction pathway is a complicated process that requires a lot of factors to work properly in order to reach the desired response, and because this process is so complicated there are a lot of chances for something to go wrong. First of all, mutations in signaling molecules could cause it to be unable to bind to the receptor and therefore the whole signaling transduction pathway will not be able to occur. This same situation can happen if the receptor was mutated, hence the signaling molecule won't be able to bind to the receptor. The next place where something in the pathway could be altered is during transduction. If one of the relay molecules is mutated this could stop the process from finishing or it could result in a different (potentially harmful) response to the initial signal. Certain chemicals can also affect signaling transduction pathways by either activated or deactivating a process and change the cellular response that happens.  Segment 3: Connection to the CourseAlteration in signaling transduction pathways can lead to diseases such as type 1 diabetes or cancers. This is why it is important to understand how the steps in the pathway works and where things can go awry. If we can understand where the issue is taking place that causes cancer or causes diabetes, we can help the individual by disrupting the cancer signaling pathway or giving the patient insulin. The signaling transduction pathway is used in the body all the time, whether it be during the cell cycle or after we eat some glucose and that's why it is crucial to understand the mechanisms by which it works so we can combat issues that may arise during it.  Thank you for listening to this episode of My AP Biology Thoughts. For more student-ran podcasts and digital content, make sure that you visit http://www.hvspn.com (www.hvspn.com). Eat a cookie you gotta make sure those insulin receptors still work from time to time!  Music Credits: "Ice Flow" Kevin MacLeod (incompetech.com) Licensed under Creative Commons: By Attribution 4.0 License http://creativecommons.org/licenses/by/4.0/ Subscribe to our Podcast https://podcasts.apple.com/us/podcast/my-ap-biology-thoughts/id1549942575 (Apple Podcasts) https://open.spotify.com/show/1nH8Ft9c9f6dmo75V9imCk (Spotify) https://podcasts.google.com/search/my%20ap%20biology%20thoughts (Google Podcasts )   https://www.youtube.com/channel/UC07e_nBHLyc_nyvjF6z-DVg (YouTube)  Connect with us on Social Media Twitterhttps://twitter.com/thehvspn ( @thehvspn)

My AP Biology Thoughts  Unit 4 Cell Communication and Cell CycleWelcome to My AP Biology Thoughts podcast, my name is Victoria Villagran and I am your host for episode #90 called Unit 4 Cell Communication and Cell Cycle: Cellular Responses in Signaling Pathways. Today we will be discussing general cellular responses in signaling pathways.  Segment 1: Introduction to Cellular Responses in Signaling Pathways Signaling pathway: Signaling begins with the recognition of a chemical messenger, a ligand, by a receptor protein in a target cell The ligand-binding domain of a receptor recognizes a specific chemical messenger, which can be a peptide, a small chemical, or protein, in a specific one-to-one relationship Signal reception, which is when the target cell receives a signaling molecule; transduction, which is a series of events that converts the signal to something the target cell can respond to; and cellular response, which is when the target cell responds to the signal.  They are many varieties of ligands and receptors, and them binding can lead to many different responses  May involved 2nd messengers or phosphorylation, and protein phosphorylation  They all produce some kind of cellular response The same signal or ligand can lead to different responses  Signal Pathways may influence how the cell responds to its environment  Responses can be short or long term We can see changes such as an increase in the transcription of certain genes or the activity of particular enzymes. We may be able to see changes in the outward behavior or appearance of the cell, such as cell growth or cell death, that are caused by the molecular changes Three Response Types 1. Metabolism/Growth/Enzyme Activation/Open Ion Channel Altering the activity of specific enzymes, metabolic enzymes in the cell become more or less active  Activated G Protein binds to a molecule that starts the transduction pathway, we will go into more detail later  Some signals bind to ligand-gated ion channels which either open or close in response to binding  2. Gene Expression The process where information from a gene is used by the cell to produce a functional product, a protein. It involves two steps, transcription and translation. Signaling pathways can target either or both steps to alter the amount of a particular protein produced in a cell. Intracellular receptor: ligands are small or non-polar and can diffuse into the membrane. They are an activated hormone-receptor that can act as a transcription factor and affect gene expression Controlling which genes are expressed or not through a number control mechanisms  3. Apoptosis: programmed cell death in cell cycle (also T cell Recognition) Internal signals (such as those triggered by damaged DNA) can lead to apoptosis, but so can signals from outside the cell.  Segment 2: More About Specific Cellular Responses  Metabolism: Epinephrine  When epinephrine binds to its receptor on a muscle cell (G protein-coupled receptor), it triggers a signal transduction cascade involving production of the second messenger molecule cyclic AMP (cAMP). This cascade leads to phosphorylation of two metabolic enzymes, causing a change in the enzymes' behavior. The first enzyme is glycogen phosphorylase (GP) which breaks down glycogen into glucose. Phosphorylation activates glycogen phosphorylase, causing lots of glucose to be released. The second enzyme that gets phosphorylated is glycogen synthase (GS) and it is involved in building up glycogen, and phosphorylation inhibits its activity.  Through regulation of these enzymes, a muscle cell rapidly gets a large, ready pool of glucose molecules. The glucose is available for use by the muscle cell in response to a sudden surge of adrenaline aka the “fight or flight” response. Apoptosis: External Signaling  Most animal cells have receptors that interact with the...

My AP Biology Thoughts  Unit 4 Cell Communication and Cell CycleWelcome to My AP Biology Thoughts podcast, my name is Arthur Kim and I am your host for episode #84 called Unit 4 Cell Communication and Cell Cycle: The Endocrine System. Today we will be discussing the role of the endocrine system in cellular signaling and communication.   Segment 1: Introduction to The Endocrine System The endocrine system is the means by which cell signals released by internal glands travel towards their destinations.   Endocrine signaling is how cell signals are transmitted across long-distances. A gland releases a signal into a circulatory system, usually the bloodstream, where it is carried about until it is picked up by the appropriate receptor.   Segment 2: More About The Endocrine System As the body is relatively large, it is essential for signals to be able to be transmitted across large distances. The pituitary gland, the so-called “master gland,” is located just slightly below the brain -- however it is responsible for regulating functions across the entire body.   Example -- When sodium levels in the bloodstream rise, the pituitary gland sends antidiuretic hormones into the bloodstream where they are eventually circulated to the kidneys, which respond by releasing water into the bloodstream. The pituitary gland also uses the endocrine system to circulate hormones to other glands in order for them to release hormones when needed. It directs the thyroid gland, located in the neck, in order to control metabolism. It also directs the adrenal glands, located in the kidneys, which produce numerous hormones like adrenaline, aldosterone and cortisol. Segment 3: Connection to the Course As cell signaling across long distances is central to our functions, the endocrine system is essential in allowing for us to exist the way we do. The ability for cells to communicate across long distances has allowed for life to grow and become more complex.   Thank you for listening to this episode of My AP Biology Thoughts. For more student-ran podcasts and digital content, make sure that you visit http://www.hvspn.com (www.hvspn.com).   Music Credits: "Ice Flow" Kevin MacLeod (incompetech.com) Licensed under Creative Commons: By Attribution 4.0 License http://creativecommons.org/licenses/by/4.0/ Subscribe to our Podcast https://podcasts.apple.com/us/podcast/my-ap-biology-thoughts/id1549942575 (Apple Podcasts) https://open.spotify.com/show/1nH8Ft9c9f6dmo75V9imCk (Spotify) https://podcasts.google.com/search/my%20ap%20biology%20thoughts (Google Podcasts )   https://www.youtube.com/channel/UC07e_nBHLyc_nyvjF6z-DVg (YouTube)  Connect with us on Social Media Twitterhttps://twitter.com/thehvspn ( @thehvspn)

My AP Biology Thoughts  Unit 4 Cell Communication and Cell CycleWelcome to My AP Biology Thoughts podcast, my name is Saarim Rizavi and I am your host for episode # 83 called Unit 4 Cell Communication and Cell Cycle: The Nervous System. Today I will be discussing everything there is to know about the Nervous System. I'll start off by giving a brief introduction into what the nervous system exactly is, the parts of the nervous system, what these parts themselves consist of, and the function of these parts. I will then get into how the nervous system develops as one grows older and the many life-debilitating and common diseases of the nervous system. I will finally place the nervous system into the broader topic of cell communication and the cell cycle by talking about the cells of the nervous system, the cell signaling pathway of the nervous system, and basically how neurons communicate with one another. So, basically, I'll be talking about how the nervous system actually works. I actually want to study neuroscience in the future which is focused on the brain and its impact on behavior and our functions and the main focus of the field is how the brain sends messages throughout your body through the nervous system. So I'm happy to be talking about this topic and I hope you guys find it interesting too. Before I begin, I would like to give credit to some of the websites and resources that were used to create this podcast. These include, lumen learning, mayoclinic, the National Institute of Health, News-Medical.net, livescience.com, and Khan Academy.  Segment 1: Introduction to The Nervous System What is the nervous system? A complex network of nerves and cells that carry messages to and from the brain and spinal cord to different parts of the body The main controlling, regulatory, and communicating system in the body and is known to be the most complex and highly organized body system The center of all mental activity including thought, learning, and memory.  Responsible for maintaining and regulating homeostasis Allows us to interact and understand our environment and surroundings, internally and externally Has 2 main parts, the central nervous system and the peripheral nervous system The Central Nervous System Made up of the brain, spinal cord, and neurons The brain controls many of the body's functions including sensation, thought, movement, awareness, and memory The surface of the brain is the cerebral cortex - associated with perception, memory, association, thought, and voluntary physical action The largest part of the brain is the cerebrum - responsible for things such as memory, speech, voluntary behaviors, and thought.  The cerebrum is divided into the right and left hemispheres  The right hemisphere controls movements on the body's left side, while the left hemisphere controls movements on the body's right side  The hemispheres are divided into the frontal lobe, the occipital lobes, the parietal lobes, and the temporal lobes  The spinal cord connects to the brain via the brain stem and runs down through the spinal canal, located inside the vertebra.  The spinal cord carries information from various parts of the body to and from the brain and in the case of some reflex movements, responses are controlled by spinal pathways only Neurons are the building blocks of the central nervous system.  Billions of these neurons can be found throughout the body and communicate with one another to produce physical responses and actions. The Peripheral Nervous System Made up of nerves that branch off from the spinal cord and extend to every part of the body Main role of the peripheral nervous system is to connect the central nervous system to the organs, limbs, and skin  Nerves extend from the central nervous system to the outermost areas of the body  The peripheral nervous system allows the brain and spinal cord to receive and send...

My AP Biology Thoughts  Unit 4 Cell Communication and Cell CycleWelcome to My AP Biology Thoughts podcast, my name is Nidhi and I am your host for episode #95 called Unit 4 Cell Communication and Cell Cycle: CDK and Cyclins. Today we will be discussing what cyclins and CDK are and why they're important.  Segment 1: Introduction to CDK and CyclinsCyclins are a group of related proteins, and there are four basic types found in humans and most other eukaryotes. These include G1cyclins, G1/S cyclins, S cyclins, and M cyclins. Each cyclin is associated with a particular phase, transition, or set of phases in the cell cycle and helps drive the events of that phase or period. For instance, M cyclin promotes the events of the Mitosis phase, such as nuclear envelope breakdown and chromosome condensation. Cyclin-dependent kinases, or CDKs, are enzymes that catalyze the phosphorylation of target proteins in the cell cycle. The attached phosphate makes the target protein more or less active. The CDKs are activated when attached to cyclin because the cyclin changes the shape of the enzyme. When a cyclin attaches to a Cdk, it has two important effects: it activates the Cdk as a kinase, but it also directs the Cdk to a specific set of target proteins ensuring that those are proteins appropriate to the cell cycle period controlled by the cyclin. After the phosphorylation of proteins is complete, cyclin breaks down and CDK is inactive. CDK-Cyclins also act as a control or regulator for the cell cycle. Cdk activity and target proteins change as levels of the various cyclins rise and fall. In addition to needing a cyclin, Cdks must also be phosphorylated on a particular site in order to be active. Segment 2: More About CDK and Cyclins An example of how cyclins and cdks work is the mitosis-promoting factor. A MPF molecule is a CDK bound to an M cyclin. As the cell approaches the G2/ Mitosis transition phase in the cycle, the levels of the M cyclin increase. It then binds to CDKs present in the cell and together they cause the Mitosis phase to begin. The MDF adds phosphate to protein in the nuclear envelope, causing it to break down, and activates chromosome condensation promoting targets. In addition to driving the events of M phase, MPF also triggers its own destruction by activating the anaphase-promoting complex/cyclosome or APC/C, a protein complex that causes M cyclins to be destroyed starting in anaphase. The destruction of M cyclins pushes the cell out of mitosis, allowing the new daughter cells to enter G1.  CDKs and cyclins often respond to cues from the cell to regulate. Positive cues, like growth factors, increase activity of Cdks and cyclins, while negative ones, like DNA damage, usually decrease activity. When DNA damage occurs, a protein called p53 triggers the production of CDK inhibitor proteins. These proteins bind to Cdk-cyclin complexes and block their activity, allowing time for DNA repair to occur. By ensuring that cells don't divide when their DNA is damaged, mutations are not being passed onto daughter cells. When p53 is defective or missing, mutations can accumulate, potentially leading to cancer  Segment 3: Connection to the Course Cylins and CDK can connect to the principles of evolution. Cyclins and Cdks are found in many different types of species, from yeast to frogs to humans. They vary slightly in each organism. For example, yeast has just one Cdk, while humans and other mammals have multiple Cdks that are used at different stages of the cell cycle. These common enzymes and proteins can provide evidence of a common ancestor between these species.  Thank you for listening to this episode of My AP Biology Thoughts. For more student-ran podcasts and digital content, make sure that you visit http://www.hvspn.com (www.hvspn.com)!  Music Credits: "Ice Flow" Kevin MacLeod (incompetech.com) Licensed under Creative Commons: By Attribution 4.0 License...

My AP Biology Thoughts  Unit 4 Cell Communication and Cell CycleWelcome to My AP Biology Thoughts podcast, my name is Shriya Karthikvatsan and I am your host for episode #81 called Unit 4 Cell Communication and Cell Cycle: Cell Communication. Today we will be discussing how cells communicate with one another and how they do over long and short distances.  Segment 1: Introduction to Cell CommunicationSo, the topic of cell communication focuses on how a cell gives and receives messages with its environment and within itself because a cell's survival depends on its ability to receive and process information outside its environment The cell membrane plays a key role in a cell's response to environmental signals because there are chemical and physical signals that a cell has to respond to via receptors  In membrane signaling, proteins shaped into receptors are embedded in the membrane which connect the triggers in the external environment to the ongoing dynamics inside a cell In addition, ion channels allow the direct passage of molecules between external and internal compartments of the cell Cells have evolved a variety of mechanisms to be able to transmit important biological information and some examples include: The development of growth factors that interact with the cell membrane and can trigger receptors that powerfully affect the http://www.nature.com/scitable/topicpage/p53-the-most-frequently-altered-gene-in-14192717 (modulation of gene expression) Metabolites in the blood that can trigger a cell's receptors to cause the release of a hormone needed for http://www.nature.com/scitable/topicpage/g-protein-coupled-receptors-pancreatic-islets-and-14257267 (glucose regulation) Now, we will go into an overview of cell communication and some important terms to note Since we know cells communicate using signals, we should also know that these chemical signals are proteins produced by a “sending cell” which are released into the extracellular space where the signal can be “heard” In order to detect a signal, or to be a target cell, a neighbor cell must have the right receptor for that signal When a signaling molecule binds to its receptor, it alters the shape or activity of the receptor, triggering a change inside of the cell and signaling molecules are often called ligands The message carried by a ligand is often put through a chain of chemical messengers inside the cell which leads to a change in the cell, such as alteration in the activity of a gene or cell division Finally, the original intercellular (between-cells) signal is converted into an intracellular (within-cell) signal that triggers a response You can see what I am talking about in the diagram below: In the next segment, we will go more into detail of the 4 types of cell signaling, their meanings, and why they are important Segment 2: More About Cell CommunicationCell-cell signaling involves the transmission of a signal from a sending cell to a receiving cell, but not all cells exchange signals in the same way because cells are exposed to many signals and may have different responses  The 4 basic categories of cell signaling are, autocrine, juxtacrine, paracrine, and endocrine signaling with the main differences between them being the distance that the signal itself travels So, first, in autocrine signaling, the cell signals to itself and a great example of this are tumor cells because of their ability to produce and respond to their own growth factors The cell releases a ligand that binds to receptors on its own surface or to receptors inside of the cell This signaling is important because during development, cells take on their own identities and reinforce them In juxtacrine signaling, direct contact between cells is required, and the transfer of signaling molecules transmits the current state of one cell to its neighbor which allows a group of cells to coordinate their response to a signal that only one of them may...

My AP Biology Thoughts  Unit 4 Cell Communication and Cell CycleWelcome to My AP Biology Thoughts podcast, my name is Corrinna and I am your host for episode #88. This is Unit 4 Cell Communication and Cell Cycle and today, we will be talking about transduction phosphorylation cascades Segment 1: Introduction to transduction: phosphorylation cascadesTransduction is the second step in cell signaling pathways. It comes after reception, where the signal (which is called the ligand) is received by the receptor.  In order for the signal to start a response in the protein, the receptor needs to be activated. For the cell to produce a response, the next proteins in the chain also need to be activated. These proteins can be activated and deactivated like an on/off switch.  One of the ways that the signaling molecules are activated is phosphorylation. For a molecule to be phosphorylated, phosphate is added to the molecule. Phosphate groups are typically linked to either tyrosine, threonine, or serine, since these amino acids have hydroxyl groups in their side chains.  Phosphorylation is what can activate or deactivate the signaling molecules. It can also make the proteins more active (like an enzyme) or cause it to be broken down. Additionally, phosphorylation generally isn't permanent. To de-phosphorylate a protein, cells have enzymes called phosphatases that remove the phosphate groups from the phosphorylated protein.  A phosphorylation cascade is when multiple signaling molecules in the cell signaling chain are phosphorylated, which transports the signal to another molecule to produce the end result.  Segment 2: examples of transduction: phosphorylation cascadesIn order to better understand phosphorylation cascades, let's look at an example.  One example of a phosphorylation cascade is the epidermal growth factor (EGF) pathway.  When growth factor ligands bind to the receptors, the receptors act as kinases and attach phosphate groups to each other's intracellular tails. These receptors are now activated, triggering a series of events. Since these events don't include phosphorylation, we won't cover them in detail and will instead talk about the parts after that series that do involve phosphorylation.  Those events activate kinase Raf. This activated Raf phosphorylates and activates MEK, which in turn phosphorylates and activates ERKs. The ERKs then phosphorylate and activate other target molecules that then promote cell growth and division.  This specific pathway is called a mitogen-activated protein kinase cascade.  Because this specific pathway used multiple phosphorylation events that triggered other phosphorylations, it can be classified as a phosphorylation cascade.  Segment 3: Connection to the Course Phosphorylation cascades are extremely important in cell signaling pathways because they allow the cell to respond to more than one cell signal. Phosphorylation cascades trigger multiple cellular responses, because the phosphorylation of one protein leads to the phosphorylation of another.  Additionally, if phosphorylation cascades become out of control, especially cascades that signal for growth factor, cancer can occur. This shows that being able to stop cell signaling is extremely important, since if cell growth and division goes unregulated, it becomes dangerous.  To stop cell growth and division, the cell may receive a signal to undergo apoptosis, or cell death. This usually happens if a cell doesn't pass a checkpoint in the cell cycle, which is explained in further detail in another episode.  Thank you for listening to this episode of My AP Biology Thoughts. For more student-run podcasts and digital content, make sure that you visit http://www.hvspn.com (www.hvspn.com). See you next time on My AP Biology thoughts Podcast! Music Credits: "Ice Flow" Kevin MacLeod (incompetech.com) Licensed under...