[Music] hello welcome we are live for the first time on YouTube super excited to be studying with you to get ready for the AP Bio exam it is so soon so soon I mean obviously AP exams started across a lot of classes this week and I know that we're all a little stressed so if you're taking the time to come study with me tonight I really appreciate it um a lot of good information that's going to be coming your way uh but let's start with introductions so I am Melanie Kut I'm from the absolute recap and I am the host of a handful of things so here we have um just to get started we're going to be doing the binge right and so since the absolute recap started with a podcast we are binging the content right and so whether you are here from the podcast or whether you're here because of the ultimate review pocket um we're all getting ready to prepare for the exam so first and foremost welcome um there's a couple of things I want to make sure that you have at your fingertips in order to be ready the study guide okay so if you look at the top of the comment box you you can see the the link that's included to make sure you can download the study guide that goes with this presentation in just a second I'm going to walk you through how to get it take only a couple minutes to download and once downloaded you'll be able to interact with the presentation take some notes on the side um and really get ready for for the test second let's use the chat um I want to make sure that we're being respectful right everyone's here maybe with a different level of content knowledge and that content knowledge can be uh a little unsettling right if you hear someone else that might seem like they have their their their answers really Snappy and they have the information at their fingertips and maybe that's not you yet that's okay let's help each other so please be respectful in the chat I will answer as many questions as I can as I see them come through uh our structure tonight is going to include some practice questions as well so if you think you know the answer answers pop them in the chat um and we'll try to work out some of those misconceptions so let's talk about how to get this study guide once you click on the screen at the top of the chat you're going to see a link to take you to the ultimate review packet and so this ultimate review packet will add you directly to the ultimate review packet page to biology when you are on the page you can just take a quick scroll and see that the urp includes a lot of things including allate units we have our practice exam and answer keys um but most importantly right what's included with a free preview that third tab down says live exam review and whenever you see that free preview button that's going to tell you that you don't need to have any access to the urp other than signing up for a free preview account to get these resources so the steud guide that you want to download is right here units 1 through 4 live the review study guide um and in order to get that you're going to click free preview at the top and you can log in with either your Google account or make an account um but you can see that the price here is 0 when you have that downloaded you will be able to access the study guide right the study guide is going to include information on these slides some of the practice questions as well as place for you to take your notes so with that let's get started um once again I'm Melanie kit I'm from the atsol recap and we are going to be able to review today the podcast resources you can really access them anywhere um we're across YouTube with the podcast we are also going to be over on the uh Spotify Apple music uh Amazon has a playlist streaming service as well all of that is going to be um where you can download the podcast we have over 86 episodes obviously if you're here on YouTube we are going to be using YouTube as well and there's a lot of content on here with more coming um in the future that you can access at any time um and of course the ultimate review packet three of the resources that we have to help you get ready for the exam but I need to take a quick second and Shout out my friends uh there was a really funny comment the other day online about Mrs Tiffany Jones at AP biop penguins and that in some way perhaps we are Rivals uh we are actually very much social media friends and YouTube friends um Tiffany AT AP biop Penguins I'm sure there's some AP Bio Penguins here tonight um joining us for this live so if you are looking for some free resources if you're looking for just like a really good emotional support for the exam I've linked her website down in the description you can ask access that she has tons of quizzes really responsive on Instagram has a Q&A box that she will answer your questions for you um so check out that for sure the other thing that I want to make sure you are accessing is deep learning so deep learning is an AI tool for a variety of AP subjects they have teamed up with content creators like myself that will um allow you to ask cont content specific questions and it pulls information from all of my scripts right so anything that I've written for the podcast or for YouTube can be used with deep learning um and that also has a quiz function some f frq grading functions and so I've also linked their resources for you down in the description below so feel free to check those out too um and my other friends at the urp right the bottom of my YouTube page it'll have all of their content Pages linked everything that they have free for you so if you're taking AP Bio you're probably taking another AP exam and that's going to be um an important thing for you to really access as much support as possible and many of the resources are also free you don't have to necessarily get the ultimate review packet but if you're looking for extra practice uh you can absolutely do so all right here we go let's zoom in one of the biggest phrases we use on the podcast um getting down to those details so we're going to cover units one through four tonight and I specifically have the percentage breakdown that the CED that's the course exam description has for each of those units um the course exam description is like the the the Holy Grail of all of the AP classes it's not a secret it's not just for teachers you can go Google it uh it has all of the core content and the core skills that you need to know for each AP exam that being said there is more that you have to know that's not in the CED it's just kind of like the Baseline information for you to apply based on all of these breakdowns you can see chemistry of life really gets the short end of the stick but the content from chemistry of life unit it shows up throughout many of the other units so although it doesn't have a lot of emphasis individual ually and really it's never had as far as I can recall um its own frq it's going to be integrated into other into other content we're going to go through unit 2 three as well as four and um typically unit three is not everyone's favorite uh we'll kind of take out some of the scary from cellular respiration and photosynthesis for you in our conversation tonight all right unit one chemistry of life zoing all the way in microscopically on a molecular level so learning objectives these are directly from the CED I'm not going to spend any time on them at this moment but you can see that these are the goals of the unit I have them copied for you in the study guide and so you're welcome to see those as you um download that document but I am going to pause here because as a teacher who constantly gets asked um Mrs King it do we have to know this for the test uh there's always the what don't I have to study can I take any shortcuts can I can I just not worry about some information and the answer is yes so the AP uh CED actually excludes information and tells you things that you don't have to know so in unit one this is going to be specific structures of nucleotides right so you don't have to visually be able to tell the difference between adenine and thyine within a nucleotide you should know they're they're one ring two ring components but structurally where are the nitrogens that's not necessary amino acids you don't have to be able to tell me what methionine looks like um but if they show you methionine on a diagram and tell you it's methionine then you should recognize oh here's the R Group here I have my carboxy here's my amino group um all of those pieces of amino acid structure important but not the specific amino acid itself the same is true for polysaccharides um starch versus cellulose they'll give you the diagram it will be labeled um but you shouldn't have to identify what it is individually and also the same is true for lipids so if you've had to do that in the past for your teacher just know it's not an expectation uh for the exam all right can't start without water now water is one of the most amazing molecules on Earth and it forms polar coent bonds within the molecule of water and so if we look at the label diagram here uh which I drew we can see that there are extra veence electrons on that oxygen which is not being bonded to the hydrogen and so the oxygen is more electronegative it's actually going to hold those electrons closer to the oxygen atom as compared to the hydrogens and so we end up with a molecule although it's not charged it has an uneven distribution of charge and that's going to mean that we are uh going to create a molecule which has opposite sides molecule that has one side that will act one way and another side that acts another way this is the foundation of hydrogen bonding because hydrogen bonding is a weak intermolecular force it's not actually a bond um but just like the starfish is not a fish hydrogen bond not a bond but it will cause water to have really distinct properties those properties are cohesion right when water is attracted to other water molecules we have adhesion water attracted to other things that either are polar or charged um and this creates lots of properties like surface tension high specific heat it also causes ice to have a lesser density than liquid water because we form a crystalline structure when those hydrogen bonds push apart but water it's amazing it's going to be involved in lots of our chemical reactions including hydrolysis and dehydration synthesis and so thank you water all right moving into our macro molecules we have carbs Now 1 to two to one is our carbohydrate uh Elemental ratio so if we think of a classic glucose C6 h126 this is going to be um important to the either ringed or branched structure but carbs are only going to have those elements now when carbs join up uh like for example here we have sucrose you're not going to have exactly a one to two to one ratio but that's because we have had um dehydration synthesis at that glycosidic Bond we are in monosaccharides as our monomers forming uh polysaccharides as our polymers they are polar and they have a lot of functions so glucose I already mentioned is going to come back again very shortly uh you can also have structural carbohydrates like cellulose um in plant cell walls proteins uh big fan of proteins when and doubt it's a protein that's what it does um and so when I look at my monomorph structure here I find an amino group um I have my carboxy group there's a hydrogen and then the variable R Group and that's where the plug in play will matter very few amino acids actually have sulfur but I that's why I kind of have it in parentheses it's not super common um nitrogen in our amino group one of the two places we see nitrogen in our macro molecules but CH H and O they're in everything so they're not really going to give any clues as to which molecule you are looking at the excuse me the parts that we see on the side so the way in which the protein is going to fold is really significant because this is going to influence the behaviors that our protein has we want to be very cautious in the way that we describe proteins losing function um structure influences function huge theme of biology but the structure needs to have um very specific uh pieces like liter locations in which smaller units will bind when you take a protein and you have a very specific fold it's going to fold that way because of the R Group interactions and those hydrogen interactions that we see with my um two sides of my amino acids the amino group and the the car boxal group those are going to be bonded to an adjacent amino acid forming a polypeptide chain so those aren't going to influence folding it's those other Elemental pieces that will when in doubt a protein does it we're going to go through protein a ton when we do protein synthesis I see someone asked in the chat are we going to have a unit 5 through eight absolutely it's next week um I think it's on Tuesday I will recap kind of all of those pieces for you um later on just back in in the chat real second I was having a technical glitch so I want to say uh hello to everyone this live is going to be an hour I'm already going too slowly so maybe an hour and 20 it will be saved um AP biop Penguins recommended me to you oh I love that Kyle thank you she's the best um San Diego hey awesome awesome awesome all right we are going to do um a couple practice questions coming up super shortly so keep going in the chat because that's exactly where we're going to want to put our responses all right lipids lipids are nonpolar uh except for phospholipids so lipids are ch& o you're going to find a greater ratio of hydrogen to oxygen um than you saw in carbohydrates it's one of the clues that you have a lipid because like the straight chains can look really really similar when we look at lipids there really is no true monomer because there's just a lot of diversity right you have fused carbon rings when you have um steroids you can find here uh triglycerides and also phospholipids right phospholipids kind of steal the show but it's the phosphate group because it has a negative charge that makes this molecule anthathi meaning that the non-polar tails are not charged but we're going to find a polar head due to that phosphate group which will cause the Bayer structure as it does and I just want to point out here in this diagram we have two types of fatty acid chains one with a double bond um which is going to be unsaturated and one that is straight right so saturation refers to a literal Elemental saturation um of those hydrogens function here energy storage structure liens which we're going to mention very very shortly if you think you remember what a Lian is let us know in the chat um and we will discuss that when we get to communication all right last one nucleic acids c h n p they have every element of chops but sulfur and here we are concerned mostly with directionality number one as well as bonding patterns with our um nitrogenous basis so directionality I'm specifically referring to the order of the the carbons on my carbon ring that is going to influence whether I'm five Prime to 3 prime or three prime to 5 Prime so the phosphate group is going to be attached to the five Prime carbon whereas the adjacent nucleotide is going to be attached to the three prime carbon coming off of my One Prime is going to be the uh nitrogenous base either puring or permiting single or double uh ringed difference between RNA is going to be uracil we also have double versus single stranded we're going to regroup on nucleic acids again later on so I don't want to give them too much attention right now signaling molecule great job Sophia yes a lan is a signaling molecule all right let's get ready to practice so if you have the study guide this is a great place to to interact with the diagram if you don't have the study guide still not too late to go grab it at any point throughout this presentation it's linked at the top it's totally free um it's a PDF download it's eight pages uh so that you can back up with all of this um with all of this uh don't worry I see a comment here uh I don't remember a thing this is unit one stuff I personally do unit one in like eight days with my students in August so if this is a little bit fuzzy for you uh it's also really small portion of the exam looking at a 2020 uh CED question here uh scientists examined the folded structure of a purified protein resuspended in water and found that amino acids with nonpolar R groups were primarily buried in the middle of the protein whereas amino acids with polar R groups were on the surface of the protein so of that which of the following best explains the location of amino acids in the folded protein information about non-polar R groups kind of huddling up in the middle and we have polar R groups on the surface of the protein so kind of sticking outward couple options here if you think you know the answer please pop it into the chat so two choices justifying uh the polar R groups being on the surface because they can form ionic bonds with charge things polar R groups are too bulky to fit in the middle of the protein and are pushed towards the protein surface uh non-polar R groups cannot form hydrogen bonds with water are pushed into the middle of the protein so here we have some repelling action and then non-polar R groups from different parts of the protein form calent bonds with each other to maintain the protein structure so why is the protein folding in this way couple votes for a see a couple votes for C all right and C is the best answer of this question yes they cannot form hydrogen bonds and so part of that is going to cause a rep um being repelled from the water molecules and pushed into the middle of the protein this is a really similar reaction to what we see with the phospholipid Tails right and as to why they kind of huddle in the middle of that by layer great job everybody okay unit two I was fast I know there are no elephant sized amibas uh cells have to stay super super super small for a lot of reasons uh the amoeba is actually the one of the mascots of the absolute recap so we are uh fond of amius here and although they are one of the bigger produs um they are not going to ever get so large that uh they can't function right that would be not ideal all right learning objectives let me get a little larger here so you can see them double digits you can see unit 2 has a ton of information this is all on your study guide here's what you don't have to know you don't have to know specific smoothie R functions like how it's involved in lipid synthesis uh how the GGI is going to be involved um in that as well or how it packages specific enzymes for vesicles it's just a level of detail they're not going to ask of you but I will be honest many students who've take AP Bio have taken uh look I'll call it baby bio or bio 101 before the course they learn some bad habits when it comes down to the organel so don't mind me while I Soap Box briefly um as an AP grader I see uh a lot of correct information that will not earn points when it comes to organal and so this is often due to students simply restating a function of an organal or the or some sort of analogy of what the organel does unfortunately on the AP Bio um it's not going to be deep enough um for this the the ones that have asteris come back in later unit so in terms of like what the might what the um organal importance is they repeat multiple times and so it is going to be more likely there'll be questions on those since they show up in multiple units my advice to you clearly you should know what the organal do um but think about it from a different perspective right so imagine the organel breaks right there's something that goes wrong what's going to happen as a consequence of that change right so if something is interfered with or there's a mutation of instruction how would that impact the the relaying functionality of that organel and so when we look at some example questions that's what we will see um question I saw over here do we have to know how to draw the macro molecules you do not um that is not an expectation of the CED um that you have um Kyle don't be afraid of amibas it's okay all right let's get right into practice let's see what we remember about our organel here we have a pathogenic bacteria that's been engulfed by a phagocytic cell as part of a non-specific naate immune response which of the following illustrations best represents the response so if I I were to look at all these diagrams right off the bat a few things I'll notice um this poor bacterium is being uh engulfed some sort of pseudopods being wrapped around it being brought in by a vesicle it's also leaving every choice in in the same way so nothing about its entry or exit is different so here we're left with ribosomes in a antibodies in b c has lomes involved D has the mitochondria so of these which of these organel is most likely going to show how this immune response is going to function right so you don't have to know the immune system for the exam you actually don't have to know anybody body systems for the exam but this is a good example of uh applying your information to the to the concepts you do have to know a lot of votes for C let's take a peek the answer is c um ribosomes are involved in protein synthesis antibodies are not a non-specific response so those are structural proteins that will be uh designed to specifically attack and you typically break down an invading forward body and The Last Choice here is the mitochondria mitochondria involved in cellular respiration so that's not going to be involved either so the lomes are like Lysol Angela thank you for that and uh analogy here great way to remember that they are involved in intracellular digestion and some sort of cleanup function uh just make sure that you don't use the analogy on the actual exam but whatever whatever helps us to kind of trigger our brains I'm all here for it all right surface area to volume ratio and this is why there are no elephant sized amibas surface area is a 2d concept volume is a 3D concept and so as we get larger the um there's going to be a limited ability for the cell to be efficient right so if you get too big you can't take in food and nutrients fast enough to kind of nourish the core of your cell if you get too big you can't get rid of waste fast enough and by fast enough I mean either through diffusion facility diffusion active transport whatever your mechanism happens to be still has to go through your barrier right your your plasma membrane and so um I like to uh think about this from a perspective like if you're going to some type of uh some type of sports arena or or game and you're exiting the stadium and they only have like three exits open you're in traffic for at least an hour the concept of that is that if you have to wait in line to go through a specific barrier and you're actually like a toxin well then the cell is not going to survive so surface area is that literal physical uh space that that has to be moved through in order for the cell to achieve its its metabolic functions uh this is on the formula sheet and I'll be honest uh it's there it's rarely used by students during the exam it's kind of like a formula like security blanket if you will don't memorize any formulas um it's just not we really don't memorize most of that but it's really just not it's not a good use of your time it's referenc you can reference it at any point um throughout the exam but surface volume ratio is really why so many things have folds indentations um to allow for greater activity across those surfaces so the mitochondria is a great example the inner Christi that inner membrane highly highly highly folded meaning it has a lot of membrane within the organel that's going to allow for a lot of ions to move across that membrane a lot of proteins to be embedded in that membrane and that's going to allow the the mitochondria to function the best that it can all right let's move on to our next unit two concept an unlabeled diagram what was I thinking okay obviously the phospholipids are there with blue and black tails does anyone know what the yellow is in this diagram and why it is placed where it is it's not on the perimeter of the it's not on the perimeter of the of the phospholipid membrane at all it's inside the tails what is the yellow in this diagram pop into the chat if you know I'm going to focus in the purple while you guys answer that question so here I have two purple structures uh one being hot dog shaped looking like a protein Channel formed from one side of the membrane to the other the other is a peripheral protein um being involved in some sort of attachment or cell signaling great job yes the yellow is a steroid it could be cholesterol um within the membrane influencing St St uh fluidity of that membrane all right and lastly we have the Green in the diagram these are going to represent carbohydrate chains involved in cellular recognition um and at times cellular signaling so you'll find those as well um in the cells cell diagrams can vary so dramatically um I like to draw my own because I do find that it it allows it to be present in a way that I don't get stuck on one specific version of what it should look like and the the likelihood is you're going to see things on the exam you've never seen before or are represented in a way that you're not as comfortable with so exposing yourself to lots of different diagrams and at times honestly they're like excessively simplified on the AP exam um because the the fluff like the extra stuff is gone they just want you to focus on specific things and they might not even label like structurally have them might just be a label like this is what this is um in this space so I do encourage you to look at a couple of different diagrams for different things try to caption them um in your own words as we go through all all right yes those carbs are for cell identification they can be involved in that uh kind of like cell labeling as well all right looks like uh my slide got a little wonky from the transfer it's uh not quite lining up here so I might have to verbally go through a couple of these things I apologize for that it looks like it didn't transfer well so transport transport through the membrane we have two categories here that which uses at p and that which does not so no ATP used means that the reason molecules are going to cross the membrane is that they're going to go from a high concentration area to a low concentration area this is passive transport it can occur with with these molecules moving directly through the membrane like osmosis or diffusion um or through a protein which would be facilitated diffusion uh difference between the two is if you're going to pass directly through the membrane you must be small and non-polar water although polar super small and in small amounts it can fit in between phospholipids if you need to move a lot of water all at once from high to low you're going to have to move through a protein it's called an aquaporin so that would be classified as facilitated diffusion but it's still all passive and the reason that these molecules are moving um high to low is really just they're bumping into each other there's a lot of kinetic energy as the molecules go from um an area where they're more crowded to where they are less crowded and they are more likely to go from high to low it doesn't mean they will exclusively go go from high to low um but they're just more likely to move in that direction on the other side if you have to use ATP you are going to be pushing molecules into an area where they are already more crowded you're going against their concentration gradient doesn't necessarily mean they're even going to be able to fit over there they're often going to be large or they're charged um moving through a protein I think the well most famous I guess if you can if you could be a famous protein pump uh sodium pottassium pump gets a lot of Glory uh moving sodium and potassium ions which are charged in opposite directions across the membrane and then we have other movement through vesicles like endo and exocytosis that example that we just had with the bacteria being engulfed that was going to be an example of endocytosis uh this this diagram is not wonky in the study guide so apologize for that but you can use a study guide for the correct one all right uh osmolarity is a scary concept for some uh because of the math water potential calculations are on the formula sheet and I know I'm not going through those calculations tonight we're we're going to do a little bit of that in the final review um if you're tuning into that the night before the exam just kind of some some last minute math uh but I have some some broad notes here first of all tenacity when we're describing hypertonic isotonic hypotonic we're specifically describing solute concentration um and so the concepts that we use with that is is going to influence two things if the solute can move right if it can move across the membrane in which direction and why right so high to low is going to be the general movement of solutes from hypertonic to hypotonic if the solute can move water is going to move in the opposite direction because water follows its own concentration gradient so if you have a hypertonic solution means you have a lot of solutes you must have a lesser concentration of water you have a lower water potential less free water available and so water tends to move in the opposite direction as my solutes but what's important to note here is the the water's going to go whether there's space forward or not and so these are going to lead to situations of Lis at times if water moves in Faster then an organism can maintain its balance uh so we see this at times with par parium parium are are normally in saltwater environments they're typically in hypertonic environments and if you expose them to fresh water or hypotonic you don't get any more hypotonic than pure water water rushes into the cell now a parium does have a contractile vacu that can actively squeeze and pump water out of its out of its cell but if the rate of moving water moving in is too great it's going to rupture that uh that cell membrane so we get conditions in different types of cells with um cells having triger pressure if you're a plant cell because it's full Central vacu you can have situations in which cells shrivel right if it loses a lot of water in an animal cell that we call that crenation so all of these water movements can have real consequences for for really organisms as uh as we go through all right time to practice uh as I pull up the question I'm going take a peek at the chat and see what I missed as we go through so here we have starch and glucose um with water this is actually a really really common uh lab that is done in some ways trying to see how a a fake cell right um will H will change depending upon um depending upon the certain condition so as you guys uh thanks for cheering each other on um in here uh college board thanks for popping into the chat appreciate you uh checking in keeping up the good work virtual teachers yeah virtual please give me a five I don't think it works like that Valeria but it's not you know what maybe if you tweet at Trevor Packer and just say Hey listen I went to a live review with the absolute recap I would love to get a five if the College Board would do that for me that would be amazing um all right hello AP biop penguins so we have a couple penguins in the chat oh you did this lab Angela yeah I love this lab um there's a lot of variations of it in terms of describing the the differences that you can see so you might have done it with starch and glucose you might have done it with salt um that's a really common thing for this as well all right so what do we think the answer is here which excuse me which is going to represent which is going to represent here um the best justification for the movement that we see and before you kind of jump into the answers and see a couple of them happening already be mindful of your axes right what the axes are representing ah Mrs Jones getting a lot of love in the chat yeah Angela so your C said food coloring what happened in your lab with the food coloring were you were you tracking was it an iodine lab were you tracking where the starch would be just curious looks like a lot of us have gotten an example here um of what we think the answer should be so let's look here at a and why we believe the answer to be a looking at our levels of water starch and glucose we can see that starch um has the relative amount in the bag staying constant we see glucose decreasing and water increasing and that's going to show the movement here now starch isn't changing starch is huge starch is really large right Star as a polysaccharide it's not going to move through that dialysis tubing um yeah very very easily right maybe you poked a big hole through with a pencil or something you would end up with some starch have time break we are halfway done so I am 10 minutes farther than I thought I would be but let's take a second where is everybody from I'm I'm kind of stealing I think you can't see it anymore I'm from Philadelphia I have a Philly poster in the background of all my videos um but where are we located throughout the recap first I don't I don't think that's a thing um throughout here I got a message from someone who wasn't able to join us in the live today and was really really hoping it would be recorded um because it was uh 400 a.m. in Israel and they weren't going to be able to log in Costa Rica Houston Austin New Mexico awesome Wisconsin love it California what time is it in California and are you in the part of California where I'm going to be jealous of your weather that would be that' be very sad for me although it was 80 degrees here today so we'll take it Georgia 3:40 a.m. Mar where is that and why are you awake I mean thank you for coming oh I can't wait to see where Martha's from but I really do appreciate you guys coming to this live it's been um a really for me a great experience to interact with all of you and and hear about the questions that you have um one of the reasons you get into science is because students have an interest in finding out like what they don't know and how does all of this work so it really is fantastic um that you're able to to dive into me and if this is your last science class I would be very sad this is your first science class please take many more um but we are excited to have you uh here Michigan all right we do have India in here thank you oh yes Martha make sure you sleep before your test all right guys we're going to keep going um take a quick stretch okay quick stretch if you're sitting at the computer we um Martha you're in Africa what part of Africa there's lots of Parts um Kyle you're welcome Monaco I've I've been to Monaco Monaco's fun all right if you haven't grabbed the study guide yet okay if you haven't grabbed the study guide yet it's not too late jump into the packet so I have the top of the chat that kind of pinned link for you that's where you want to go and the free preview free pre Zer right free preview includes more than just this study guide so it's all of unit one for free everything that's in there it's half of unit two for free it's a couple other things and like unit three unit five so if you would like some extra things um you definitely want to to grab that okay all right we are going to move on to everyone's favorite I know that's not true I'm pretending all right everyone's favorite unit three cellular energetics um I'm currently actually also teaching physics and uh laws of thermodynamics like you just have to obey them and unit three is the emphasis and the example of how and why that's true so cellular energetics is kind of a vast unit everyone typically just thinks of um photosynthesis and cellular respiration uh we will have a couple of uh couple of Concepts same thing learning objectives they're in the steady guide I'm going to skip them here's what you don't have to know you don't have to calculate pH or Gibbs free energy so if you took apem and you are scarred you don't have to do that here but the next one's big you don't have to know specific steps molecules enzymes of Calvin Krebs or any of the electron carriers or any intermediate molecules in the electron transport chain that is huge because I do know that some teachers um in AP Bio have um have have asked that of you and I don't I don't fault them for it I think I think I do a lot of it in my own explanation because I think it's a fuller picture of what's Happening um but you don't have to you're going to have information in the diagrams to reference should you need them right they're gonna ask you a question about the KB cycle there's G to be a diagram most likely of the kreb cycle for you to interact with in some way the answer won't be overtly on it but it should trigger your brain um as we as we go through that so let's I will come back to those when we get to those sections but enzymes first they're made of protein so they have to follow all of the protein Like rules we'll say active sight for your substrate substrate that is specific to the shape of that substrate and if that active site changes shape because the protein has has um been modified either through an inhibitor that's aleric or competitive or perhaps the enzyme has been denatured in some way due to changing environmental conditions that's going to be a problem now oftentimes we're we are use the expression that enzymes speed up the rate of reaction and I'm using air quotes um the uh rate of reaction does typically increase but enzymes just make re reactions more likely to happen and they do this in a lot of ways but one of them that we typically talk about is lowering activation energy they make act uh those those reactions more favorable they don't require as much energy to occur because they're bringing molecules together in a specific way uh the two graphs that I have for us here do have Gibs free energy on them just available energy when we're when we're working through a calculation and if the products store more energy than the reactants did that would be endergonic and then we have exergonic when the energy is released to another thing right not destroyed but released to another thing all reactions require energy to occur it's just whether the products are going to be at a higher or lower energy State than the reactants so enzymes in a nutshell personally I don't really do this in unit 3 I covered with unit one stuff with my students um but this is included here biop Penguins asking if Winnie is going to visit Winnie's not g Winnie's currently snoring upstairs I can hear her uh that would be our our Bulldog mascot but no she's not coming all right time for a practice question make it big for you here we have the enzyme Tron which AIDS in protein digestion in the small intestine no you don't have to know anything about the small intestine to answer this question but on my graph I can see relative acidity and oh excuse me relative activity and pH on my X AIS ranging here from 0 to 12 and I can see that the peak occurs around pH of 8 so enzymes are really picky uh they're just they're condition specific right so this particular enzyme seems to like a pH of eight now why which of the following statements best explains the activity levels of tripson shown in this diagram that is a key part of the sentence shown in this diagram right so the information here has to link back to figure one has to link back to figure one so is it going to be because the small intestine releases inhibitor molecules is it going to be because there's just uh a number of effective collisions between Tron and a substrate at higher pH is it going to be um because as pH values increase substate concentration decreases or is it going to be that at low PH values tripson is denatured and cannot function effectively all right energy cannot be created or destroyed that's correct get a nice shout out all right we're all down there with D um great job guys looks good um I do want to pause here just talk about collisions so as you increase in temperature I recognize that's not what this graph is saying but as you increase in temperature you do increase kinetic energy and so you do increase enzyme activity because you have greater collisions between substrate and active site but if you increase the temperature too much you're going to end up with a denat protein so there's a there's a a fine line before we have to swap back to something different ah there it is energy cannot be created or destroyed just transformed from one into a another ATP answer the prompt no that's a different acronym but I fully believe it and I will talk about it on the final exam review day this is our friend that carries energy from one place to another our little energy shuttle constantly uh removing that third phosphate to be a DP and an inorganic phosphate through hydrolysis and then being reattached through ATP synthes in either of our electron transport chains so we're going to see this guy a lot as our primary energy currency as the analogy States it's not however the only molecule that's going to transfer energy for us in these processes within our uh cells okay now if you've been scarred by photosynthesis before I'm sorry but we can get through this together as I stated previously you don't have to memorize the steps you also don't have to know um the many of the molecules so the goal here is what goes in what comes out where and what's the Machinery involved in this process um and so the the photos is broken down into lots of Parts meaning like it has nine different names light and dark reaction light dependent and light independent Etc and the Calvin cycle tomato tomato um it's all going to be describing the same function within different parts of the cell so double membrane here because the endosymbiosis Theory stacks of thids which have a lot of surface area and then a liquid stroma all right starting on the left left then we'll go to the right steps of the photosynthesis when we look at the overall equation we want to find the players where are those pieces of the puzzle being used right the goal of photosynthesis is to build sugar glucose eventually we are going to do this by inputting water and carbon dioxide and removing from this process excuse me oxygen and our sugar don't fall in the Trap the gases don't go together meaning water splits during the light reaction releasing oxygen when we have oxygen being released we're not getting those oxygens from carbon dioxide I know it can kind of be uh confusing in that way because we assume the gases go together um but that's not going to be how the process works so light strikes the electrons it excites them to a higher energy level and they travel through the electron transport chain everything in green here is part of that chain different shades showing different roles and the roller coaster that those black dots those electrons go on is because they are losing energy as they pump hydrogens across the membrane and they are recharged by uh in the second photo excuse me the first photo system which happened second um to transfer energy to our electron carrier right our nadph molecule which will shuttle energy over to to the Calvin cycle when we have this accumulation of hydrogen ions that build up they are going to develop an electrochemical gradient great concentration also electrically charged and so they will flow passively back through the membrane through ATP synthes and that's going to assist in the formation of ATP that phosphorilation um of this molecule the Calvin cycle is going to receive energy from the electron chain and use that energy to physically manipulate these carbon molecules and form my three carbon sugar so all of the carbons from carbon dioxide go into the Calvin cycle independently Calvin cycle CHS we put together a g3p molecule um a three carbon molecule in order to um receive that uh that product so we actually have to do the Calvin cycle twice to end up with a six carbon sugar uh that will be uh be formed at the end so what goes in what goes out and why the electron transport chain happens first to First capture energy transfer to the Calvin cycle the Calvin cycle turns in the stroma forming those sugars photosynthesis and a nutshell all right cellular respiration three to four steps depending upon how many breakdowns you want to do the glycolysis step is going to be Universal all organisms can do it whether you have oxygen or not because it does not require oxygen to be accomplished even even as it is the first step of cellular respiration it is not going to have oxy as a reactant yet so when we look at the process of cellular respiration oxygen does not actually have its debut until the very very very end of this entire chain so if you have oxygen we will take our broken down glucose molecule our pyrovate um and we will through a series of stacks oxidize it and it'll go into the mitochondria if there's no O2 we'll going to follow a fermentation pathway there's a couple versions here we could do alcoholic fermentation which will uh produce a carbon dioxide byproduct um because we're going to remove a carbon in that or we might do lactic acid fermentation which is a three-carbon product so we we don't produce gas in that situation but the goal is not to make ATP there's actually no ATP made in the fermentation pathway it's just going to regenerate NAD plus right so we formed nadh we need to reform nad+ and so fermentation Pathways just the LA glycolysis to occur again normally NAD plus the enzyme carrier is going to excuse me electron carrier is going to be recycled after it was used in the cellular respiration pathway so we want to make sure that we um send that shuttle back uncharged uh so glycolysis can happen again so that's really the only reason fermentation Pathways even produce any ATP it's because glycolysis did it in the first place uh pyate oxidation is it's a lovely phrase right it always gets overlooked uh when you go from pyate to acetal COA yeah glycolysis does make two pyrates because if we look at the amount here uh six carbons cut in half three and three each pyate molecule will go through the rest of cellular respiration independently all right so in synthesis we went electron transport chain and ended with the cycle in cellular respiration we have the cycle first ending with the electron transport chain so the processes are like a mirror image and this really reinforces um the idea that we have uh reciprocal equations right if you flip it around you have um really really concrete um pieces so what goes in what comes out where and why when we look at the crab cycle we are in the mitochondrial Matrix right the fluid portion of the Matrix so we have Cycles happening in the fluid portion of each respective organel and the goal of this is to physically continue to break down all of my carbons from my original glucose molecule so pyro gets oxidized to acetyl COA acetyl COA is going to go into the cycle and we're going to remove the carbons as the cycle churns which is why carbon dioxide leaves the crab cycle right CO2 comes off we also going to get some electron carriers that will help us move through the electron transport chain which is going to occur in the inner mitochondrial uh inner mitochondrial membrane but the process is really similar we drop off electrons from those electron character carriers they go through the chain the movement of those electrons actively pumps across hydrogen similar to how we saw in photosynthesis we build up an electrochemical gradient and they flow back through ATP synthes so all of those kind of big picture Concepts still play out in cellular respiration as ATP synthes um has the hydrogen ions moving through we are going to form a system of formation of ATP all right let's practice we are almost done unit three hitting the hour mark so we want to wrap up shortly it's estimated that oxygen production first evolved in photosynthetic procaryotes approximately 2.7 billion years ago the first photosynthetic procaryotes are presumed to be similar to today's cyanobacteria which of the following best supports the claim that the procaryotes were responsible for the oxygen in Earth's atmosphere all right what do we think so if you think you know pop it into the chat ah I want yes I see some things in the chat talking about nadh and N um plus reduction is when it does gain that electron and hydrogen yeah so we lose the positive in that so we think of the nadh like holding on to the energy and NAD plus is not um NAD H in cellular respiration soes a nearly identical function to NAD pH in photosynthesis and they both are going to be electron carriers for that looks like we are split a little bit between A and B let's take a peak B is going to be excuse me our correct answer here um as we look had really the question is asking like where did the oxygen come from and so if we look at the process and look at the steps that's going to be where we see our our oxygen from the splitting um uh splitting of water when it first strikes the photo system [Music] okay last unit and this is going to be a short one um as we move through so unit four cell communication and cell cycle one big game telephone should be simple [Music] right all right learning objectives again they're on your study guide grab it in the chat if you haven't here's what you don't need to know um you don't need to know any specific cycling cdk pairs or growth factors so even within the cell cycle excuse me in the cell cycle and within diagrams they're going to be labeled for you but you don't have to know them specifically thank God for the mute button I'll tell you that much all right three primary steps steps reception transduction and response I grabbed this diagram on purpose if you look down in the corner you can see where it came from 2022 AP Bio FR frq number one one of the challenging things about signal transduction Pathways is how you're not required to know any specific pathway it would be so much easier if you could just like have one in your brain and just use that as your example every time that's just not the way that it works and so this particular diagram I really like because you know they're going to show you a couple of different options of how things become activated and inact activated how they relay information from one area to another all of which starts with a Lian so the Lan will bind either extracellularly or intracellularly based upon its own chemical makeup so in this diagram we have a um extracellular Lian that would imply that it's not non-polar or maybe it's really large and it can't fit through the membrane when when we have transduction we can be involved in taking a really small signal and just causing a significantly large relay system this might involve several protein kinases it might involve um phosphor relation Cascades it might involve secondary Messengers so a secondary messenger would be something that um perhaps calcium maybe the liend itself didn't cross the membrane but it caused a channel protein to open and then you had a literally a secondary messenger crossing the membrane to then continue the signal so there's a lot of variation here my best advice when it comes to cell communication Pathways is just a look at a lot of examples and the best ones are in fact in the CED looking at the ones that are frqs that have already been released um and then the response really common to have responses that are protein synthesis related um sometimes the responses will be uh vesicle formation related but in in many ways cells have to communicate about lots of things so on the exam they're just going to have to give you um enough information uh for that uh question to be answered just reference back the diagram and use the terms off the diagram itself but let's give it a go so insulin is a protein hormone that is is secreted in response elevated blood glucose levels when insulin binds to its receptors on liver cells the activated receptors stimulate phosphor lean Cascades that cause the translocation of glucose Transporters in the plasma membrane all right what's the role of insulin in this paragraph what is the role of insulin in this paragraph you think you know the answer pop it into the chat in this example this is a good representation though of the fact that all these questions will have real world application so they're not going to be made up they will have real world applications all right overwhelming responsive a in the chat great job um protein hormone so it's going to bond um it's it's going to bond extracellularly it's not going to be able to diffuse feedback mechanisms two types negative and positive key thing here is that it's going to have some information relative to homeostasis so homeostasis is a buzzword for you but you're kind of blanking on the definition let me just regroup it so homeostasis the maintenance of constant internal conditions despite external changes so this is the body's ability to respond to stimuli from its external environment as well as internal conditions and all of that is to kind of keep it in its goldilock Zone most feedback loops are negative it's going to bring the organism back to homeostasis back to the area where it is um most functional positive feedback loops are very temporary but they have a really strong purpose in allowing organisms to typically thrive in stressful or like um life or death or or reproductive temporary moments um and so there's not as many examples of positive feedback loops um child birth lactation in mammals is a good example as well um and the way that your blood clots is also um is also really a good example let's do a a quick practice all right here we have some blood clotting which of the following best explains the feedback mechanism based upon the picture I see things labeled like smooth muscle collagen Epi endothelial cells endothelial cells is probably something you didn't study you likely Also may not know blood vessel structure but what we do see here is uh chemicals being released we see a circle an arrow kind of curving back around showing that continuation um as we go so which explains the feedback mechanism Illustrated in this figure okay I see a couple in the chat some C some C some a all right so it is a but let's look at C so this is an example of negative feedback because a large clump of platelets can block the blood vessel and prevent blood flow through it so the the the full the curved Arrow here is an intentional process we have to remember that the intentional process of returning to set point returning to normal wouldn't really be describing negative feedback because negative feedback if it impedes the blood flow that's not going to be a homeostasis condition um so that would be why C is not correct Okay the reason why it's a is because platelets are causing more platelets and this clotting is not a standard condition of the of the body right and so we have a leak in the blood vessel here these chemicals are causing more platelets to come and close that hole we wouldn't typically want that to occur um within within an organism all right cell cycle checkpoints looking through here we have interphase consisting of G1 s and G2 uh there are a lot of checkpoints within here to ensure the cells should continue throughout its growth uh process the the uh way that this is described and you often see M phase identified with um mitosis and then Sak Kinesis they are separate processes but they have to ensure that the um the the right parts are connected so often we're going to look for damage do we have spindle fibers attached do we have um all of our chromosomes have they been uh replicated we ready for the next phase not shown here is G but G is that non-dividing stage that some cells will go into instead of continuing through the um s phace all right and lastly here mitosis mitosis looking through and distinguishing between different parts and pieces so remember mitosis is a process of cell division as we move through pmat prophase metaphase anaphase and tase to divide chromosomes evenly and create diploid cells so the sister chromatin structure the x that we see in mitosis is going to pull apart an anaphase and it's going to allow identical sister chromatids that were formed in the esates to migrate to opposite poles of the cell this is possible because during metaphase all of my sister chromatids line up in the middle spindal fibers shorten pulling those um components apart so when we get to meiosis which we won't until unit five we'll notice that the chromosomes align in the metaphase um in metaphase differently and the way that my pairs separate will be by homologous here I'm separating sister chromatids in mitosis I'm maintaining my chromosome number so diploid 2N I'm still diploid 2N um in the in the resultant cell so need to form identical cells um at the end of mitosis so to recap we have neared the end four units here looking through chops that we have proteins carbs lipids nucleic acids water is amazing and it's polar in cell structure and function we have surface to volume ratio we have organel that are involved and cells really compartmentalize their functions to transport materials in and out cellular energetics don't break the rules of thermodynamics energy cannot be created or destroyed but it's transferred sunlight into sugars is photosynthesis sugars into ATP is cellular respiration and enzymes are reusable they're not going to be um destroyed in a chemical reaction they're not a reactant um they are substrate and condition specific lastly in cellular respiration on the cell cycle we have the reception transduction and response you have feed back loops with homeostasis and cell division and checkpoints with mitosis and Pat so coming up next on the absolute recap we have the May 8th which is tomorrow night practice test um next week we will yes I have a question in the chat we will do units 5 through eight and then on May 15th we will have a final review there'll be two of them um the one on YouTube will start first um and then there will be a a a live stream for ultimate review packet subscribers only that will be a little bit longer and occurring after that so I want to say thank you so much for coming um and I hope that you found this helpful I did not quite stick to the hour um hour mark but I appreciate all of you coming to study with me and your participation in the chat your support of each other is absolutely amazing um I really feel strongly about this community that we have here at the recap and if you think this was helpful right if you think that you would like to see more of this in the future whether it be for Bio or different subject um if you think that you want to invite a buddy to the next one happy to have you and uh we we really can't wait for uh well I can't believe the exam is coming up next week this went so fast so fast um it is teacher appreciation week so if you want to say a quick shout out to your teacher in the chat I'm sure they would absolutely appreciate appreciate it they are working really really hard in these last few days they're equally invested in your success um and I know that um I know that they want to they want to see good things for you so again thank you so much for coming um yes and those of you who are up at 3: in the morning um absolutely impressive I I think all of you um all of you are going to do good things moving forward so with that I will say have a great night