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My AP Biology Thoughts  

Unit #: 8- Disruptions to Ecosystems

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Jaiden: Welcome to My AP Biology Thoughts podcast, our names are Jaiden, Adam, and Reena and we are your hosts for this episode called Unit 8, Human Stupidity and Single Use Plastics. Today we will be discussing how single use plastics cause disruptions to the ecosystem and how it relates to the AP Biology Curriculum. 

The Podcast will be broken up into three segments. The first segment will show the general overview of single-use plastics and the second segment will show how these plastics impact the environment and why it relates to the AP Biology Curriculum. Finally, segment three will discuss how we can contribute and reduce single use plastics.

Segment 1: Overview of Topic

• Plastic pollution has become one of the most pressing environmental issues
• According to the Environmental Protection Agency, Americans generated 35.7 million tons of plastic in the United States. 
• Single use plastics are plastics that are used for a brief period of time, before they are thrown away. These include plastic straws, spoons, bottles, and bags
• Microplastics are extremely small pieces of plastic debris. They are generally about five millimeters, or approximately the diameter  an eraser on a #2 pencils,  in length to be considered microplastics

Segment 2: Just how much harm is plastic causing 

• Some plastics such as Chlorinated plastics is harmful for the soil around it along with water sources making it harder for organisms to grow
• It takes 1,000 years for a plastic bag to degrade in a landfill. However, the plastic does not degrade completely but instead becomes microplastics that absorb toxins and continue to pollute the environment.
• An estimated 13 million plastic tons are thrown into the ocean each 
• These small plastic particles may harm our health once they have entered our bodies. Plastic products contain chemical additives. A number of these chemicals have been associated with serious health problems such as hormone-related cancers, infertility and neurodevelopmental disorders like ADHD and autism.
• There are now 5.25 trillion macro and micro pieces, weighing up to 269,000 tonnes. This is because every day, around 8 million pieces of plastic make their way into our oceans.
• Unlike some other kinds of waste, plastic doesn't decompose. That means plastic can stick around indefinitely, wreaking havoc on marine ecosystems. Some plastics float once they enter the ocean, though...

My AP Biology Thoughts  

Unit #: 8

Welcome to My AP Biology Thoughts podcast, our names are Ramit Dasika, Flavio D’Attilio, Samy Leroux, Landon Schafer, Colin Fahmy and we are hosting this episode called Unit 8 Ecology AND  Today we will be discussing The war between Ukraine and Russia has caused mass destruction to many ecosystems through bombings and other weaponry and how it relates to the AP Biology Curriculum. 

Segment 1: Overview of Topic

•  War 
• The war between Ukraine and Russia has caused mass destruction to many ecosystems through bombings and other weaponry
• 
  

Segment 2: Evidence that supports 

• It causes forest fires- Samy
• During the process of runoff, the harmful chemicals are collected in rivers nearby. This causes the  water sources contaminated due to chemical leakage from destroyed industrial plants-Ramit
• During the Russia-Ukrainian War, the Russian soldiers damaged and looted fire engines, computers, and radiation monitoring equipment, while leaving mines and munitions spread across the exclusion zone.-Flavio
• “In the Donbas region, wrecked sewage works gush their contents into rivers and damaged pipelines fill wetlands with oil.”- Landon
• “Most of the exclusion zone was damaged by the invasion and may be contaminated with unexploded ordnance and mines,” according to Oleksandr Galushchenko, director of the biosphere reserve. The larger mammals that constantly move around the reserve – wolves, deer, brown bears, lynx, elk, and recently reintroduced bison – are at particular risk, he says.”-Samy
• “The forests in the zone remain a radioactive tinderbox that, in the event of fires, could send radioactive isotopes on the winds towards Kyiv. The risks of that happening are now much greater, says the UNCG’s forest campaigner Yehor Hrynyk. With fire-fighting equipment looted and much of the exclusion zone dangerous for firefighters to enter, some 65,000 acres has burned since the invasion, and fires continue to smolder in underground peat.”-Colin
• “Many industrial plants are damaged or abandoned;wrecked sewage works gush their contents into rivers; damaged pipelines are filling wetlands with oil; and toxic military scrap is spread across the land.”- Flavio
• “A particular concern is the many coal mines abandoned after 2014. With pumping of water halted, they have so far released some 650,000 acre-feet of polluted mine water into the environment,...

Welcome 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. 

•  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

•  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.

•  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

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. 

•  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 

“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

•  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

Welcome 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. 

• Camping —> DOCTAH guise —-> isle royale —-> us listening to him talk :)

• Winter 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) 

• Predator-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 www.hvspn.com. 

• "Ice Flow" Kevin MacLeod (incompetech.com)
• Licensed under Creative Commons: By Attribution 4.0 License
• http://creativecommons.org/licenses/by/4.0/

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Welcome 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. 

•  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). 

• 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). 

•  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...

Welcome 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.

• 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.

• I 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...

Welcome 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.

• Have 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

•  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.

Welcome 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.

• 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

•  “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://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 
• stats
• University of Maryland: October 2018 - April 2019:

Welcome 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/ 

Background 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

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...

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.

• The 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. 

• Through 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). 

• The 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

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. 

• Antibiotics 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

• 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

• Antibiotic 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

Welcome 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.”

 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 

 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 

Keenan: 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....

Welcome 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.

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.

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

Anushka 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. 

•  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. 

•  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

Welcome 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. 

The 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.

Freshwater 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). 

The 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 www.hvspn.com. See you next time!

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Welcome 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.

• 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

• We 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

• Biology 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

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. 

• Chromosomal 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.

• During 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. 

• Chromosomal 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 www.hvspn.com.  

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Welcome 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.  

•  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.

•  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).  

•  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 www.hvspn.com. 

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• "Ice Flow" Kevin MacLeod...

Welcome 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.

• Phenotype 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

•  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.

•  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 www.hvspn.com. Bye now!

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• "Ice Flow" Kevin MacLeod (incompetech.com)
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Welcome 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. 

•  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.

•  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. 

•  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. 

Welcome 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. 

•  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. 

•  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. 

Welcome 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.

The 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.

• First 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...

Welcome 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. 

• We 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 

• Gene 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...

Welcome 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.

 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. 

There 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). 

Gene expression and regulation is important because any errors in regulation can lead to developmental problems. For example, If the tumor suppressor...

Welcome 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:

• Translation 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...

Welcome 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 

• Let'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. 

• Now 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. 

• As 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...

Welcome 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

•  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

•  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) 

•  Connection to mitosis
• S phase of mitosis is dna replication
• Necessary for cell division to make the same amount of chromosomes in...

Welcome 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. 

•  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. 

•  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,

Welcome 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.

• First 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. 

• From 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. 

• Tying this back to the overall ideas in Unit 5, mendelian genetics corroborates the...

Welcome 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!

•  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 

•  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...

Welcome 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.

•  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.

•  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...

Welcome 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.

• X-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. 

• One 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. 

Welcome 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

•  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. 

•  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.

•  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 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/

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Welcome 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. 

• So, 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 modulation of gene expression
• Metabolites in the blood that can trigger a cell's receptors to cause the release of a hormone needed for 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

• Cell-cell signaling involves the transmission of a signal from a sending cell to a receiving cell, but not all cells...

Welcome 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.

● 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

● 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...

Welcome 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. 

•  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...

Welcome to My AP Biology Thoughts podcast, my name is CJ and I am your host for episode #80 called Unit 3 Cellular Energetics: fitness. Today we will be discussing molecules and metabolic pathways

•  This is a much different type of fitness taught back in the evolution unit. This fitness is in energetics and we mainly look at the variation in molecules that allow the organism to survive and/or reproduce in a different environment. The whole point of this fitness is to see how organisms change when a new condition is introduced. For reference, when we stand still and have normal amounts of oxygen, our body uses aerobic respiration, meaning we get energy from the oxygen around us and our body goes through cellular respiration. However when we are running or going through conditions with limited amounts of oxygen, our body switches over to anaerobic respiration. This switch still allows us to get energy, however not as much. This change shows us how fit we are and ties into how our body changes with the different environment. However, that example was just a general overview, in fitness we look at the specific molecules. 

•  If we want to look at more examples we have to separate plants and animals. A main example of important molecules that provides for the animal is hemoglobin. This cell is found in the blood, and this is the main transporter of oxygen throughout the body. The oxygen bonds to these molecules and it is then transported through the bloodstream to all of the different cells. However, hemoglobin changes and adapts to its environment. We see that hemoglobin binds to oxygen differently throughout stages of life. For fetuses, their hemoglobin is different in terms of more oxygen being able to bond to it. This is because fetuses do not expend as much energy as an adult, however it needs more oxygen for metabolism and growth. The fetal hemoglobin then is able to attach to more oxygen molecules, however that means it is much harder to get oxygen off of the hemoglobin. This is why adults use a hemoglobin that attaches to less oxygens, but it is easier to separate. Now for plants, the main example of fitness is chlorophyll. With low amounts of light, the plant typically uses chlorophyll b which is more of a pigment than a center for photosynthesis. With higher levels of light, the plant typically uses chlorophyll a, which is the main reaction center. 

•  This directly relates to the unit by connecting cellular respiration to the real world. We learn about aerobic and anaerobic, however we don’t learn when we use them and under what conditions. But more importantly, we don’t learn what the molecules do to adapt to this. This chapter allows us to conceptually understand why our body does what it does. It is essential to know the connection between variation in the number and types of molecules within cells that allows the organism to survive under different ecosystems.

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

Welcome 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.  

•  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.  

•  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.

•  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 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

Welcome 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

•  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. 

•  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.

•  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

Welcome to My AP Biology Thoughts podcast, my name is Sid and I am your host for episode #86 called Unit 4 Cell Communication and Cell Cycle: G Protein Receptors and Tyrosine Kinase Receptors.

•  G Protein receptors and tyrosine kinase receptors both work to mediate cell communication by binding a signaling molecule, which is also called a ligand. Then this signal is sent through a transduction pathway where the last target protein causes some response. The response for both can be a variety of things such as gene expression, apoptosis, metabolic responses, cell division, or cell growth. Despite being similar in this way, g protein receptors and tyrosine kinase receptors work in very different ways

•  Let's start by discussing g protein receptors. G proteins are very diverse and can bind to many different signals. One example is odorant (or scent) receptors. G proteins receptors are located in the cell membrane which is where an extracellular ligand binds to it. The signal is eventually sent to a g protein which is located on the membrane, but on the cytoplasmic side. Before the G protein is activated, GDP is bound to it which keeps it inactive. GDP is guanosine diphosphate. After the signal binds to the receptor, the receptor slightly changes shape and becomes active. Then, the GDP binds to the g protein receptor. Since the G protein no longer has a GDP bound to it, it frees it up to accept and bind to GTP. The GTP activates the G protein. The G protein is made up of three subunits: alpha, beta, and gamma. When the GTP is bound to the G protein and activates it, the alpha subunit detaches and moves away from the receptor. Now the G protein is split into two parts: one part is the single alpha subunit and the other is the beta and gamma subunits. These two parts can go on to interact with other proteins and cause a transduction pathway that results in one of many responses. Eventually, the alpha subunit comes back and hydrolyzes the GTP which keeps the G protein active and changes it back into GDP. At this point the G protein will once again become inactive. G proteins coupled receptors are very important in the human body. Disruptions can cause diseases like cystic fibrosis or cholera. 
• Now let's talk about tyrosine kinase receptors. Tyrosine kinase receptors are enzyme linked receptors. Enzyme linked receptors are receptors that are associated with an enzyme. A kinase is a protein that phosphorylates other proteins. For tyrosine kinase receptors, the kinase phosphorylates tyrosine. To start the process, a signalling molecule attaches to two tyrosine kinase receptors. These come together and form a dimer. Then, each tyrosine kinase receptor phosphorylates the domains of the tyrosine kinase receptor. Then, once the tyrosine is phosphorylated, it can send signals to other molecules

•  G protein receptors and tyrosine kinase receptors are very important to many species. Problems with g protein receptors can cause choler,

Welcome to My AP Biology Thoughts podcast, my name is Adrienne and I am your host for episode #94 called Unit 4 Cell Communication: Mitosis. Today we will be discussing the steps in mitosis and its connection to the cell cycle and regulatory processes.

Before we get into the steps of mitosis, lets first define what it is. Mitosis is the division of a cell nucleus to form 2 identical daughter cells. Some important words to know so we can understand this process include chromosome, which consists of 2 identical halves called sister chromatids and are attached by centromere, sister chromatids, which are a single, tightly coiled molecule of DNA, chromatin, which is condensed DNA that coils around protein, and spindle fibers, which attach to the sister chromatids of the centromeres and pull apart the chromosomes. 

So now that you know those definitions, let's dive into the steps of mitosis which include prophase, metaphase, anaphase, and telophase. In order for mitosis to begin, each chromosome must have two chromatids that were previously formed during S phase of interphase. In prophase, many processes occur including the chromosomes condensing in order to protect the DNA, the centrosomes moving to opposite poles, the nuclear envelope breaking down, and the microtubules connecting to the centromeres. Next is metaphase where the chromosomes line up on the metaphase plate, which is the plane between the two poles of the spindle. Then, the microtubules pull each chromosome apart into two chromatids. The significance of this step is that it ensures that all DNA chromatids separate when the cell cycle is functioning normally. Then, anaphase occurs where the microtubules shorten and pull the chromosomes to opposite poles so each pole has a complete set of chromosomes that have the same number as the original cell. Lastly, mitosis ends with telophase where it reverses the processes from prophase. The previously broken down nuclear envelope and nucleus begin to reform, the chromatin decondenses, and the DNA unwinds from the histone protein. Specifically in animal cells, a groove forms called the cleavage furrow as the purse strings are tightened and the cell splits into two. At the conclusion of mitosis, two daughter cells are formed, each with two identical copies of every chromosome but each chromosome only has one chromatid.

To connect mitosis back to the bigger ideas of cell communication and regulation in unit 4, let’s take a look at how mitosis occurs. One way cells control division is through cyclin-dependent kinases which are enzymes that advance cells past checkpoints. They phosphorylate target proteins in the cell cycle and when activated, they attach to cyclins which change the shape of the enzyme. This sends chemical signals which either turn on or off cell division. For example, mitosis-promoting factor is a cyclin-CDK complex that moves cells through the G2 checkpoint. Since G2 is the phase leading up to mitosis, MPF aids mitosis because it allows the cell to synthesize the nutrients necessary for mitosis to successfully form two normal daughter cells. This demonstrates the relationship between mitosis and cell regulation and division where cell regulatory mechanisms move cells

Welcome 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. 

•  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

• “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...

Welcome to My AP Biology Thoughts podcast, my name is Jacqueline Sun and I am your host for episode 85 called Unit 4 Cell Communication and Cell Cycle: The Immune System. Today we will be discussing how your body defends itself against infection and stays healthy through the complex yet vital immune system.

•  The immune system is responsible for fighting off germs and other harmful outside invaders from entering and wreaking havoc on your body
• Different from all other systems in that it is not a specific cell, tissue, or organ but is rather composed of several different cells, tissues, and organs working in tandem.
• There are many important components of the immune system that can be divided into two general categories: the innate (or the non specific defense system), and the adaptive (or the specific defense system).

Innate (Nonspecific defense system). As the name suggests, you are born with it and it is automatically activated in the face of threats.

• Uses physical and chemical barriers, killer cells, and fevers to defend the body
• Simple Physical Barrier is the first aspect of the innate immune system
• The skin is the first line of defense. It covers nearly every part of your outside body and acts as a physical barrier and keeps out many harmful microorganisms. As long as the skin is mostly undamaged or unharmed, its defense will hold.
• Mucous membranes also provide a physical barrier. They line the body cavities that connect the inside of your body to the outside, such as the respiratory and urinary system. The thick viscosity of the mucus aids in preventing the entry of harmful microorganisms.
• Both of these physical barriers also provide chemical defense. For example, The skin and stomach can secrete acids to kill off invaders. Sweat, which is also secreted by the skin, has antimicrobial proteins to kill bacteria. Enzymes can be found in mucus that perform the same function.
• So lets say your skin was scraped up. Now your body relies on the second line of internal innate defense.
• Your body may instigate a fever, send out chemical signals calling for defense from body parts, or cause inflammation. These are just a few of the main tactics the body may use, there are many more.

SO HOW DOES YOUR BODY DETECT WHERE THE INJURY IS AND WHERE TO DEFEND ITSELF. IT uses the...

• Inflammatory response: A bodily process that uses chemicals to signal to the immune system defenders where the damage to the body is.
• Utilizes redness, swelling, heat, and pain as signal...

Welcome 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. 

The 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. 

The 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. 

Alteration 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 www.hvspn.com

Welcome 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. 

• The 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.

• To 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...

Welcome 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

In 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!

Secondary 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...

Welcome 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. 

• Cyclins 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.

•  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 

•  Cylins and CDK can connect to the principles of evolution. Cyclins and Cdks are found in...

Welcome to My AP Biology Thoughts podcast, my name is Shriya Karthikvatsan and I am your host for episode # called Unit 3 Cellular Energetics: Overview of Photosynthesis. Today we will be discussing what exactly Photosynthesis is, its importance to life, and the processes that make up it. 

• We’re going to start off by discussing exactly what photosynthesis is, its importance, and a brief overview of the different stages of it
• Photosynthesis is when light energy is captured by photosynthetic molecules that are broken down in cellular respiration to obtain energy (ATP)
• Essentially, glucose molecules (or other sugars) are constructed from water and carbon dioxide, and oxygen is released as a byproduct
• Also, the carbon in CO2 is used to make carbs and other organic molecules that the organism requires to survive
• The process of producing the organic molecules is called carbon fixation where the carbon in CO2 is “fixed” and incorporated into sugars to be used to build the organic molecules
• Photosynthesis is important because photosynthetic organisms such as plants, algae, and bacteria play a key role
• They introduce chemical energy and help fix carbon by utilizing light energy, meaning they can produce their own food and are therefore called photoautotrophs
• Since humans and other organism cannot convert carbon dioxide to organic compounds, they rely on the autotrophs for these compounds and to receive energy 
• Also, photosynthesis is important because it produces oxygen as a byproduct which affects the Earth’s atmosphere and removes carbon dioxide from the atmosphere, preventing a gas buildup that would be detrimental to us
• Photosynthesis simplified can be divided into two stages: the light-dependent reactions and the Calvin Cycle
• The light-dependent reactions occur in the thylakoid membrane and require light energy 
• The Calvin Cycle, or light-independent reactions, takes place in the stroma and doesn’t require light
• In the next segment, we are going to go more in depth about these two processes and the specific significant parts of a plant involved in them

• Okay to start we are going to go over the important parts of a plant involved in photosynthesis you should know
• Photosynthesis itself takes place in the chloroplast of a plant which contains chlorophyll which is the pigment that absorbs different wavelengths of light from the energy source
• The chloroplasts are surrounded by a double membrane and have a third inner membrane called the thylakoid membrane where light-dependent reactions take place
• The stroma is the fluid and space in the chloroplast
• Here is a diagram of both parts of photosynthesis