Hey everybody, thank you so much for clicking on this video. As an AP biology teacher, I truly enjoy each year going through the AP FRQs that are released to the public. So this year we're going to go over it. Uh this is the 2025 AP biology FRQ test that happened on May 5th, 2025. It's really important for you to know that all the answers in this video are not official. These are my predictions. I took the time after their release today after school and I sat down and I did it myself for 90 minutes and then from there I uh created this um slide deck for me to kind of best illustrate to you what my guesses are for um each of the uh answers. Now, it's really important to know that the official College Board scoring guidelines um and samples and scoring distributions will come out usually in July 2025. So, if you're watching this after that time, go ahead and click below and I'm going to go ahead and leave a link to those um as well when they come out. All right. So, as I said earlier, timestamps for each of those are going to be below. Um uh if you want to navigate to a certain number on the APFRQ, you can do so. Some of you are watching this video because you've already took the exam and you're interested to see what the answers are. Some of you are watching this because you haven't taken the exam and you want to use this as a practice. Regardless of why you're watching this video, I hope this is helpful. And once again, below um after uh July 2025, I'm going to put a PDF um of the answers, but even right now when this video is posted, I'm going to put a PDF of the actual exam questions below. So, if you want to go in and do it on your own first, you can go and do that and then look at these uh um predicted answers. All right, cool. Please note once again, as I said uh before, these are not the official answers. These are my uh predictions and this is just me having fun and going through the FRQ um to better help my teaching as an AP biology teacher. Uh so go easy and comment below if you have any improvements or other answers that you believe that are right. Uh once again, it's also important to know that um the AP FRQ scoring guidelines when they come out, uh there's usually multiple answers. So maybe the answer I put is an answer and maybe the answer you put is going to be an answer. And uh as I've said in my previous videos, this YouTube channel is not monetized. And there's really no goal for this channel to be monetized. It's just a fun channel for me to post content on that. And and if it's helpful for you, go ahead and like it if you want or go ahead and share it with someone else. All right. What's new this year in the on the APA bio 2025 exam? Well, um different from last year. This year there was a hybrid digital exam. Then what that means is that the multiple choice was on the um um conducted on the laptop through a uh College Board Bluebook app and the um FRQs were actually um shown on the students laptop and students had to handw write them um onto a um onto a booklet that was provided by College Board. Right? So it's a hybrid this year. In the future, we don't know what it's going to be like, but that's what it was this year for 2025. Um uh it's really important to also know that uh it says on the College Board website for the exam security policies that two days after the regular scheduled exam which is already passed by now uh uh teachers and people may discuss it. So hopefully this video um doesn't um um go against any college board exam policies. I I'm just trying to learn more as I go through the FRQs and share what I've learned with my students and with whoever wants to listen. Uh it's also important to know that uh yes as you can see the college uh the questions are very secure. So here's just um some some different uh things that the calls board website talks about. And then uh the most commonly administered sets of FRQs are posted on the calls board website two days after the exam. You may have taken an exam that looks different than this and if that's so then it's probably not publicly posted. Um, but only these questions may be discussed by students and teachers. You know, every single year I get questions on timing. And you know, it's true because you only get 90 minutes to answer the six FRQs, it makes it a lot more difficult to do well on these FRQs. If you had two, three, four hours to do so, I'm pretty sure you would do a lot better. So when it comes to timing, I always like to communicate with my students that of the six FRQs, roughly the first two FRQs are about 50% of the score. Um, and then three, four, five, and six are shorter FRQs, and that's also roughly 50% of the score. So, you know, once again, everyone's going to take it differently. However, the standard rule is if you're given 90 minutes for six FRQs, 50 and the first two are worth 50% and the last four are worth 50%. It's recommended that you roughly look at 45 minutes for each of those two parts, one one and two and 3, four, five, six. So, if you break it down, if you divide 45 minutes divided by the two long FRQs, it's roughly about 22.5 minutes each. For me, it took about 25 minutes on the first F FRQ and um and on the second one as well, leaving me less time on the other ones. So, once again, work on the pacing. If you haven't taken the F um the AP F FRQ yet or if you for the AP exam yet for bio, please, please, please take a practice test and please make sure you figure out what is your strategy for timing because even when I was taking it for the 90 minutes, uh it felt rushed. Okay? So, if you feel that way, I think everyone feels that way. All right, so keep that in mind. All right, so here we go. The 2025 APA biology FRQs. Let's begin with the uh FQ number one, which is considered a long FRQ. There's about eight parts, seven or eight parts in this from what I remember. And you're given about 22.5 minutes. So, if you roughly do the math on it, it's about three minutes per question, which is very, very fast, including not including the time that you would take to read the question. All right, so let's get right to it. When you take a look at the first one, it begins with just a normal introductory question. This is what I call a gimme question. This is a question that most students will get right. I hope you get right because it's pretty um um foundational. All right, so number one, most proteins that are secreted from a cell must be transported into the ER, the endoplasic reticulum either during translation or even after translation. And all all that it asks you to do is to describe the function of ribosomes. So here's my answer. The function of ribosomes is to make proteins by translating an mRNA strand into a chain of amino acids which put together will be a polyeptide. Right? So that's number one. Uh let's uh let's go ahead and read FRQ number one. It tells you for proteins transported during translation the process begins in the cytool and pauses when a specific sequence of amino acids it's translate is translated. The translation complex is then transported to the surface of the ER where translation continues. Proteins that are transported after translation are translated entirely in the cytool in the cytoplasm and then transported into the ER. In both instances, the translated proteins enter the ER through a protein channel in the membrane of the ER. My strategy for when I took this uh during 90 minute uh during a 90-minute timer is I like to take notes on the side. Once again, you're viewing this on a laptop. So, most likely you can circle maybe you can highlight using the College Board Bluebook app. However, for for what I like to do, I like to write down some notes on the side. What I found is that when I write down notes on the side, I don't have to reread the question. So to kind of type in and to show you what I was writing on the side, you know, I just quickly wrote down that, you know, ribosomes, ribosomes form proteins and free ribosomes form proteins for the cell versus bound ribosomes on the rougher and depending on where the ribosome is is going to form proteins for outside the cell for destination of secretion of the cell. There's also a um top a um a um a um lesson on transllocation. Now this isn't the transllocation of mutations where where chromosomes can go in and switch parts but it's more so transllocation. It's where a signal can enter the ER through a protein complex. So can things go into the ER? Yes. And it's called transllocation. All right. Let's go ahead and continue reading epic number one. Researchers studying the two types of protein transport identified that the ER membrane protein SR is necessary for transport during translation while the ER membrane protein SEC62 is necessary for transport after translation. As an AP biology teacher, I can just tell you right now that we don't study the protein SC SEC62 or the protein S um SR. So, whenever the AP exam gives you these proteins or or whatever topic or name, just know that most likely none of us studied it. All you have to do is use the information that they gave you to kind of figure out what it's asking. So, I'm going to continue reading here to investigate which transport mechanism is used for different proteins. Researchers first created small interfering RNAs, which are called SRNAs, similar to mirnas that reduce the expression of either SR or SEC62. They then treated groups of cells with either the SRS SNA or the SEC 62 SRAA. So either of those and determined the relative amount of SR and SEC 62 protein in each group of cells compared with cells treated with control SIS RNA. So here's all I kind of jotted down on the side. This is kind of an elongated version. Go ahead and skip ahead if you want to go ahead and take a look at the answers. But I want to kind of walk you through how I solve this problem. SR equals necessary for transport during translation. That was stated in the question right there. And SEC62 is necessary for transport after translation. Now that will go ahead and help me in one question later on, but that's just what I wrote down. Snas similar to mirnas. They actually what do they do? If you don't know what they do is let's say you took this exam you have and you're thinking I have no idea what sas do all you just got to read the question they reduce the expression and they pretty much turn off the expression of genes when we look at chapter 18 in our epiology textbook we're looking at how ukarotic genes are regular and that's what sas do they reduce or they silence protein synthesis that's all you need to know so the problem scares you with snnas but it tells you really what it is um Then sRNAs and mRNAs can lead to something called RNAI which is RNA interference which once again is used in labs to disable specific genes to investigate their function. Right? Let me go turn back on here. All right. So siras here's a picture in our textbook about mirnas. There's actually no picture in our textbook about sirnas but the difference between mirnas and sirnas is that sirnas are double stranded. But essentially they do the same thing. I want to kind of walk you through and teach this to you. When you take a look at the picture of mRNA, this mRNA singlestranded is going to go ahead and bind to a target mRNA. From there, what is it going to do? It can do one of two things in this picture that it shows you. It can either degrade mRNA or it can go ahead and block translation, which down here I just told you sirnas, they're similar to mRNA in that they turn off the expression of genes. They reduce or silent, they stop, they halt protein synthesis. All right. So hopefully that helps your understanding. So as I continue and I look at this question and I'm doing this very quickly, but in this video I'm slowing it down to kind of tell you my my thought process. When you look at figure number one, I just quickly look at this graph. I've never seen this graph, but I'm trying to make sense of it. Here I see that the sirna added in cells or is a control group. You've got the SI uh the SEC 62 and then you've got the SR SNA. Once again, we have not learned this in our API class. This is the exam testing if you're able to make sense of this data and analyze and interpret this graph. So what I'm thinking in my head as I'm looking at this graph is that I'm looking at it in SACE62 sa when it's added as you can see right here the SR protein content shoots up and that's way over the control about 160 roughly 160%. Versus the SI sir when that's added the SEC2 protein content shoots up to about 125%. How does that even make sense? It absolutely makes sense based on what I just said earlier. What do sirnas do? They halt, they reduce, they silence protein synthesis. So if that's happening, you're not going to see, for example, right here sec 62 sa effect. Um that's why the protein content is going to be less here for SA for SR sa that's why the protein content is going to be less there. It all makes sense based on the information given. So now let's go into the answers. And if you want explanation, you can go back to how I just explained for uh FRK number one for um B1. Uh the question is identify the dependent variable. In class, we learned that the dependent variable is the x- axis. Oh, sorry, is the y- axis, excuse me, and the independent variable is the x- axis. So, what is on the e on on the y- axis shown here on the graph? Well, I'm just reading right here. It's the relative protein content percent of control. This should be a very quick answer. When I went through it, I quickly looked at the graph and I answered really quick. So if you were to write it out, you would write out something along the lines of the dependent variable or the y- axis shows the relative is labeled by the relative protein content percentage of the control. Uh specifically the protein content of SCT 2, S62 and SR protein. As you can see for B2, the question asks, justify why the researchers included the control of measuring the relative amounts of both SEC SEC 62 and SR proteins in cells that were treated with SEC 62 SRA only data shown in figure number one. So where where do my eyes go on the graph? Well, I kind of highlighted there with a little box for B2. Here's my answer. The researchers included both proteins SEC 62 and SR to show how SEC 62 protein are affected and not take a look uh the SR protein content when SEC 62 SNR is is added to cells as what I just explained earlier. All right, so that's the answer for B3. The question asks based on figure number one, describe the effect on the production of SR protein when cells are treated with SEC 62 SI RNA. for B3. Uh, here's my answer. Based on figure one, if you take a look at the graph, the levels of SR protein, I I I boxed it there in red, are not affected when treated with SEC 62 SINA. And if you're a and if you're wondering why aren't they affected, I said it a little bit earlier. So, go ahead and rewind a little bit and you can take a look at my response. The reading continues. These are long FRQs, so you have to approach it with excitement, but also with urgency because it's eight questions in about 22 minutes. So, you got to keep going. So, as I'm reading this uh once again, as I'm going over this, this is way slower than how I answered it when I took it uh for fun, which I really do take this. So, let's go ahead and keep reading. ERT number one continues by giving you information saying that the researchers then measured the amount of each of the three different proteins that was transported to the ER in cells treated with SEC 62 SRNA and SR sirna. The researchers calculated the percent transported relative to the cells treated with control SNA. All right, so here is new stuff. It then tells you that there's three proteins, one, two, and three. As you can see, here's the data. The C1 continues uh asks you identify the independent variables in the researcher second experiment data shown in figure two. All it is is the X- axis. What is on the x- axis? Here's my answer. The independent variable shown is the sirna added to the cells either the control sec 62 or or sr. That is a very simple answer. C2 here's the question based on figure two. Identify the proteins either one or two or more. It says proteins that when treated with sec62 sirna showed an increase in percent transport to the ER compared with the control. As you can see here's my answer. I believe the answer is both proteins two and proteins three as you can see as you can compare them right there uh showed an increase in percent transport to the ER in comparison to the control here I'm looking at proteins two and three as you can see they show a increase here and here okay um so that's my answer right there could be right could be wrong but that's what I got C3 is a very simple question but you got to go quick and you got to understand This is asking you, do you understand how many letters, how many uh nucleotides are going to be found in an amino acid? And we learned that a codon makes up one amino acid and a codon is made up of three nucleotides. So three nucleotides equals one amino acid. That's what it was trying to ask you if you if you knew. So here's the question. C3 protein one is encoded by 234 nucle nucleotides while protein 2 is encoded by 495 nucleotides. Assuming that all nucleotides for both proteins include amino acids. That's the key right there. Calculate the difference in the number of amino acids between the two proteins. You cannot just go 495 minus uh 234. That should be like I don't like 261. That's that's wrong. It's asking you how many amino acids are encoded. So if you look at it, here's my work. Protein number one is two. And you do not need to show your work. All you need to do is write your answer. So I did not show my work when I was answering this, which made it a lot quicker. But here's the work because I want you to know at home kind of how I got the answer. 234 nucleotides divided by three bases per amino acid is about 78 amino acids. Protein number two is made up of about 165 amino acids. 165us 78 is about 87. That's my answer. Don't know if it's right, but pretty sure it's right. Uh but that's what I got. When you take a look at D1, researchers claim that protein one is the only tested protein that is transported to the ER following its complete translation in the cytool in cytoplasm using data from figure 2 support the researchers claim. So to kind of go back to once again a lot of the times in these FRQs there's little hints in the question. So you got to read quick and you got to kind of understand what the question asks. So going back a little bit to my notes earlier when you take a look at and it's asked here let me subject 51 er figure two yes so when you take a look at this uh the SR is necessary for transport during translation and the sec 62 is necessary for transport after translation so I remember that in the reading and that's why my answer is shown as here D1 here's my answer as shown in figure two protein one transport decreases because of the addition of sec 62 and not SR are take a look at the grad. The researchers claim is then further supported because as I said earlier SEC 62 is necessary for transfer after translation. I don't think I don't think you need that second sentence but just in case you do there's a little bit of support to the researchers claim for D2. Here's a question for any protein that enters the ER. Researchers claim that amino acids close to the proteins amino acid terminus uh sorry the amot terminus determine how likely the protein is to pass through the protein channel with within the ER membrane. justify the researchers claim based on your understanding of factors that affect the transport of proteins across membranes. So, so some quick teaching real quick before I go into the answer. We learned in class that amino acids are all the same, but they're different because of their R groupoup as you can see down here. But they're the same in that all amino acids have a carbon in the middle, a hydrogen group, an amino group, NH2, and a caroxile group. Clo uh C O hydroxil. So, here's something else. We also learned in class that uh where does an amino acid um sorry, where does a protein begin? When you look at the first amino acid specifically, it's N terminal. Where does it end? Specifically, in an amino acid, uh the uh the last one, the C terminal of the caroxile group if you look at the end. So, here's my answer for D2. Proteins are directed to the ER by a signal sequence of small hydrophobic amino acids. So, that's usually what's within a protein. There's a signal sequence close to the amino acid terminus as I said earlier. Also, I don't know if you need this, but I also added in something called SRP. What is SRP? We learned in class that SRP is our signal recognition particles which will then bind to an SRP receptor protein on the ER uh membrane surface for it to pass through. So, if you have the key, you can go ahead and enter. And that's earlier what it said when it came to the channel protein. So, that was epic number one. I went a lot slower than I actually did when I actually took it within the 90-minute period, but hopefully by slowing it down, you had a better understanding of FRQ number one. All right, here we go. FRQ number two. Let's let's keep going. All right, FRQ number two begins by um giving you information that many insects rely on something called pherommones. We learned about this in class in I believe chapter 51 for animal behavior. Um chemical signals that are released by the females to find mating partners. Scientists hypothesized that in a certain type of moth, here we're looking at moths here, the behavior of male moths in response to pherommones is actually regulated by an extracellular signaling molecule, a lian called 20E. Once again, we've never studied 20E, but you don't even need to know about 20E. All you need to know is that it's a signaling molecule. A 2A asks um asks many. Okay, so here are my notes. Insects, pherommones, females to find mating partners. We're looking at moths and as I said earlier behavior male response pherommones regulated in extracellular 20 molecule 20B. So here's the first question usually once again the first question is very simple and and they want to kind of help you get some points here for 2A many receptors are embedded in the plasma membrane. Describe the polarity polar or non-polar of the portion of the receptor that is inside the membrane. In class we learned that the polarity of the portion of the receptor that is inside the membrane is actually going to be non-polar. I don't need I don't know if you need this additional information but here's what I wrote. Fossil lipid billayers are semi-p permeable because so why are certain things allowed into the membrane and certain things are not. Why? Because of the fossil billayer because of the hydrophilic heads that face outside and inside of a cell and the hydrophilic tails sorry hydrophobic tails that face inwards because of the hy hydrophobicity and the hydrophobicness of the inside of the of the cell membrane. That is what allows certain things uh not to pass. Right? Okay, then continues with some more information for efficiency number two. To investigate whether the binding of 20E to its receptor DOP EC cr we have not learned that all you need to know is that it's a receptor affects behavior in mos scientists injected male moss with saline or control solution or once again here it comes up again but once again you don't need to know too much about this other than what it's told telling you here or with something called small interfering RNAs sirnas molecules that inhibit the expression of the gene encoding dp cr. Scientists then exposed the moths to pheromone to the pheromone and determined the percent of total time observed that the moths engaged in general activity. Okay, there's general activity and then there's something later on called oriented activity which I'm going to keep reading here. Defined as movement in any direction. The scientists all determined that the percent of general activity time that the model spent in oriented activity defined as the movement towards an area of high pheromone concentration. What is the difference between those? I wrote it down down here and here. I just took some quick notes as I was writing down um some information. Typically, I don't reread FRQs twice. Why do I take little mini notes as I read? So that I don't I can just look at my notes and I don't have to reread it. Sometimes I go back and look at information, but you know that takes time. So if you're rereading this five times, you're probably not going to finish and it's all a time test. It then gives you table number one, which I quickly looked at it when I took it, but because I'm reviewing this with you, I'm going to quickly explain a little bit more. Table one, uh, we look at two different treatments. Male moths that are injected with saline or control solution. And then we've got a treatment of male moths injected with sirnas that inhibit or stop expression of that gene encoding that receptor tpc. Here we see the general activity and the oriented activity and we see some numbers. We see so real quick as I'm re taking a look at this information I'm looking at how for general activity it's about 95 and 90 okay pretty similar but then I see a big red flag or or something that stands out for oriented activity we see 60 and 25 that's a big difference versus here we didn't see much of a difference so that's all what's going on in my head as I'm reading this question as we continue reading it gives you even more it's it's a really long question ECR is a G- protein coupled receptor when 20E binds to DOP ECR are GTP displaces GDP bound to the G- protein and a signaling pathway is activated. The scientists hypothesize that this leads to the transcription of genes associated with the oriented activity observed in the male moss. Okay. So here we see GPR GPCR which is a uh which is one of the three receptors that we study GPCRs or RTKs or the gated by gated ion channels when it looks at the cell membrane receptors. But here I just wrote down that 20 E is going to bind and that's going to ultimately cause what? Transcription of genes within oriented activity. This is the picture that's shown here. We have not seen it in class, but we've seen something very similar. And I'm going to quickly go go to what we've seen in class. In class, in chapter 11, we studied cell communication. This is not a figure given on AP exam, but this picture was that we study in class. And what do we learn? Gene protein gets activated. it activates an enzyme called enol cyclace activating a secondary me um sorry um the cmp and ultimately it's going to lead to a cellular response. So how does this relate? It's actually pretty similar because here it just tells you that when the G- protein is inactive here's what's going to happen. But when the on the right when the G- protein is active it's going to lead to what it tells you an increased expression of genes associated with oriented activity in male models and this is once again on the cell membrane. So it asks you using the template in the space provided for your response, construct an appropriate type of graph that represents data in table one. So here we go to table one. Here's what we're looking at. When I graphed this, I saw that it was a comparison between the two different treatments. I saw general activity and oriented activity. And here's what I saw. So I'm going to go back here again. 95 plus or minus five. If you don't know how to do error bars, the quick way to do it is first you would draft graph 95. And here you would graph 60. But then you would the air bar is plus minus five. So we would go up to n uh from sorry 95 to 100 and then you would go down from 95 minus five which would be to 90. So what do error bars kind of tell you? They tell you if whether or not the data is statistically significant or not. So you can look more into that if you need to. But here we quickly see that for sailing control general versus oriented. And then we see for sirnas for general versus oriented we see that once again there's a big difference. General is a lot higher than oriented which is a lot lower. Now none of the error bars will overlap which means what uh and the difference will mean that the means as shown here the uh the numbers are statistically significant which means that we can take them um as we can see there. Okay. So for B2 uh we take a look at how the question asks us based on the data in table one determine a type of activity that was affected by inhibiting the expression of the DOP ECR receptor. So here's my answer for V2 by inhibiting the expression of DOP ECR receptor well um what's going to happen the oriented activity as shown here in the data table was actually affected the most okay so as you can see the inhibiting the expression of DOP ECR right here we see the oriented activity was affected the most so that's pretty straightforward for C1 it asked you based on table number one identify the treatment group in which the oriented activity was greater than 50% of the general activity. So as you can see here the general activity is shown here 95 90 what's 50% of 95 roughly about 47 47.5 something like that. So which oriented activity is greater than 50% of that general activity? Well 60 is greater than 47.5 versus 90 50% would be about 45. 25 is less than. So the answer is the saline control as you can see shown here showed oriented activity greater than 50% of the general. That's what I got. Um FRQ2 uh for C asked you the scientists studied some moss with a mutation in the gene encoding the G- protein. The mutation prevents GTP from displacing GDP bound to the G- protein. Based on figure one, predict the effect of this mutation on the oriented activity in male moths exposed to the variant. Okay, so here once again we're going back. Look at what the U image told you. It showed you that when GTP uh activates or sorry when G- proteins activated, there's an increased expression of genes associated with oriented activity in male moms. Okay, so here's my answer. C2, this mutation will actually reduce the activity because you're mutating and you're not allowing what I just said right here. It's going to reduce the oriented activity in male moths exposed to the fair. Okay? Because that's just what mutation is. That's my answer. It gives you more. But wait, there's more. And for key number two, when we look at the reading, it tells you that the expression of the gene encoding DP ECR is low in male moths during when the first few days as adults when they are sexually immature. Gene expression will rapidly increase as the moths reach sexual maturity. The scientists claim here's the claim that this increase in gene expression increases the likelihood of males finding females with whom to mate. So here's some quick notes that I took down and and as I wrote down some now once again because of time I don't actually write this out but I'm making little notes on the side pretty much telling me that the expression of gene is low in males in the first few days and but then it rapidly increases as sexual maturity and then once again I just quickly wrote down the claim because we're going to actually need that. Here's uh the question here. Use evidence from the information provided which I just read to you to provide uh provided to support the scientist's claim. Once again, what's the claim that an increase in gene expression will help males finding mates? Here's my answer for D1. The expression of the gene encoding DOP ECR, this receptor, rapidly increases as the moths reach sexual maturity, which supports the claim that this increase in gene expression will increase the likelihood of males finding females to mate with. That was my answer for D1. Here's BD2. based on figure one explain how an inhibitor of if you were to stop it of the DPCR pathway might serve as an effective uh chemical to protect crops from mock damage. So when you take a look at it if you're inhibiting the DPCR pathway here's my answer that I wrote out. D2 as shown in figure one in this chart right here. When the DOPCR pathway is inhibited, activity in males, take a look, is lowered and thus mating thus mating which leads to reproduction. If you think about a male and female remaining will lead to reproduction of more moths will be lowered the as well the lower moth population will ultimately help protect crops. is asking you um explain how it's going to help protect crops from moth damage because I would think that more moths would create a more um would lead to more moth damage. All right, that was really long. But when I took it, I was watching my time and I realized I it was I was going too slow. And even me, I'm taking so many of these, I was going too slow. So, um you got to keep moving. So, as I'm taking it, I was watching the time and and I took about 25 minutes each on one and two. So that took about 50 minutes of the uh 90 which gave me about 10 minutes on each of the uh last three FRQs which are worth about 50% of the score um including uh time to read it. So the next four are pretty quick except FQ number six. When I got to it, I had about eight nine minutes left and I realized I should have gone faster. So if you felt the same when you took it, um I get it. I got it. I get it. So here's FRQ number three. Uh, buffalo grass is an invasive species. Here, I just took some notes. I just put BG invasive. That's all I put when I was writing. Um, invasive to what? So, it it's in desert ecosystems and it's threatening something called cigaro cactus, which is a keystone species. We learned about keystone species in class. Now, this buffalo grass is also drought tolerant versus uh and it can survive a um um sorry, I'm reading and it can survive wildfires. However, the dry buffalo grass also acts as fuel for fires. So, it can increase wildfires um causing the fires to be more severe. Other cigar cacti can survive wildfires. However, many of the young cacti cannot. So, I just quickly took some notes down here as I'm reading it one time. It then goes ahead and tells you that scientists conducted an experiment to determine whether they could control the abundance of the buffalo population. The scientists identified several native grass species that when grown with buffalo might reduce the abundance of buffalo. They grew buffalo grass in the presence of several uh different native grass species in uh green houses in either non- drought watered every three days or drought watered every nine days conditions. After 12 weeks, they measured the dependent variable the height uh and dry weight of the buffalo grass in each treatment group. So I just took some notes right there and hopefully that helps out. So here's the first question. Uh 3A, describe the effect of removing a keystone species that will have on an ecosystem. You don't even need to know about buffalo grass. But here's what you should have known about keystone species. 3A a keystone species maintains an ecosystem's balance, stability, and diversity. We know that it keeps everything in check. If you remove it, everything goes out of check. So by removing a keystone species in general in any food chain, an ecosystem will not be balanced, stable, or have that diversity that we want when it comes to species diversity. 3B. Here's a question. identify a control group that scientists should include in their experiment. If you go back to the reading, it says that they're going to use several different native grass species in non- drought or drought conditions. So, here's my answer. 3B. Scientists should include a control group of what? Buffalo grass that is not grown with any native grass. So, just buffalo uh species in both non- drought and drought conditions. 3C. State the null hypothesis of the experiment in which the buffalo grass is grown in the presence of native grass species. We practice this a lot in class. What is the null hypothesis? It's not just an educated guess, but it's usually something uh that goes along with this um statement right here. Native grass species have no effect on the height and dry weight of buffalo grass. Any single time you write in the hypothesis, you're pretty much saying that there's no effect. If you're ever asked, which you weren't asked in this question, but if you're ever asked about an alternative hypothesis, as we practice in class, if it asked for that, here's what the alternative hypothesis would be for the same question, you would just write native grass species will have an effect. It's the opposite of the null hypothesis. It would have an effect on the height and dry weight of buffalo. 3D scientists have found that the population growth rates of native grasses are much slower than the population growth rate of buffalo grass following a wildfire. It just holds you right there. The scientist's claim that wildfires will therefore increase the abundance of buffalo grass plants in an ecosystem based on the information given justify the scientist's claim. So here's my answer for 3D. Buffalo grass plants, as it said in the question, have a faster growth rate in following a wild a wildfire versus native grasses. After a wildfire, there will be more buffalo grass plants in the ecosystem. That one was interesting. I pretty much just restated what the question said. So, that's me justifying the scientist's plan. That's what I got. All right, here we go. FRQ number four, right? FR here. Let's read it together. 20 million years ago, the Caribbean Sea, I just think about the Caribbean, kind of like below Florida to the side of Florida, the Caribbean islands and the Pacific Ocean, which I think is on uh the west of the west coast of the of North America and South America. Pacific Ocean were connected. So that's what was shown here in the question. And water flowed freely between the two bodies of water. Okay. Many of the same marine species were found in both areas. Over millions of years, the land referred to as uh ifmas of Panama formed. We've never learned this in class. You just kind of look at what the question gives you. Eventually closing off the connection between the previous sea and the Pacific Ocean, creating two separate bodies of water, now as we known as the Pacific and let's say the Atlantic oceans. The ecology of the Easter habits was dramatically altered by this land formation. The warmer Caribbean water as we know on the um on the east of North America uh could no longer flow west. So the Pacific Ocean cooled and became more nutrient rich which is what we know while the Caribbean water became warm. A 4 A describe the genetic evidence that evolution is occurring in a population. You don't even need to know need to know the question. You you could have just answer this based on what we've learned in biology. Here's my answer. So as we learned in class evolution occurs in a population when there are changes in alo frequencies over time. You don't need to go into it but that's why we have Hardy Wymer. Ultimately what we're doing is we're comparing before and after these alle frequencies and if there's a change then there will be evolution. If there's no change then the population is in genetic equilibrium and thus it's not going to have evolution. All right we learned that in class. 4 explain how the isolation of marine species by the formation of landberry can lead to divergent evolution. So uh species becoming different over time of those species. Here's my answer for B. Speciation as we know and divergent evolution take place when marine species in this case are separated or isolated for a long period of time and reproductive isolation is achieved. So I continued writing a new species can then form when reproductive isolation prevents gene flow gene flow mar between marine species populations due to a land barrier. Okay, that's what I got. We'll take a look at the answer when it comes out. So we'll compare that. The 4C could ask you to predict the effect of the formation of the Ithmas had on resource availability for South American species. Here's my answer. 4C. The establishment of the Ithmas of Panama connecting North and South America most likely will increase competition between land organisms. Think about it. You are separate. Now you're together most likely. So as it goes on here, justify your prediction. Most likely when connected the organisms from North America and South America which were previously had their own civil space food source and roles and niches within the community and favorable traits then they have to compete now against other species. There may be another answer but that's just what I got and we'll take a look at all right here we go. Epic key number five let's finish strong. It tells you in this question, it shows you that figure one shows the reactions of metabolic pathway used to synthesize amino acid B from amino acid A in cells. We've never seen this diagram, but you got to read it. Looks like amino acid A is like a liant. It binds to enzyme one. Enzyme one will then lead to something called intermediate X that will then bind to enzyme 2, which will then lead to intermediate Y, which will then bind to enzyme 3. It's a lot going on, which will ultimately lead to amino acid B. It looks like there's an arrow that goes back. And in class we learned that this is something called feedback inhibition and that pretty much this and it's going to um um inhibit enzyme one in this case which will then prevent overp production by regulating uh uh that um inhibiting enzyme one. Okay, so it all goes back to see. So that's all what's going on in my head. I'm not I'm writing down some quick notes but that's what I'm trying to show you what's going on in my mind. 5A finish strong. Describe a characteristic of an enzyme's active site that allows it to categorize a specific chemical reaction. Once again, you don't even need to know anything about the question. You just need to know that shape determines function. The shape of an enzyme's active site will determine its function and specificity as to which substrate will be able to bind and which chemical reaction can take place. For 5B, based on figure one, explain how the binding of amino acid A to enzyme one is regulated by amino acid B. So, here's my answer. According to figure one, the concentration of amino acid B determines the concentration of amino acid A due to what? Feedback inhibition. I said that a little bit earlier. Helping maintain the concentration of the desired level for um FRQ 5C. Here's the question. Using the information in figure one, identify the product of the reaction catalyzed by enzyme 2. Is it going to be intermediate X, Y, or amos B? Pretty straightforward here. I did it very quickly. 5C according to figure one the product of the reaction catalyzed by enzyme 2 is going to be intermediate wide shown right there on the picture D 5D based on figure one explain how a change in pH could affect enzyme 3 in such a way that amino acid B cannot be produced okay here's my answer 5 D sorry that should be 5D enzyme 3 can lose its shape and function we've learned that enzyme uh enzymes can be denatured through pH salt concentration or temperature because of dennaturation due to an environmental change in pH, thus stopping if you mess up its fun its shape, you're going to mess up its function, stopping production of amino acid B. Okay, last one, everybody. Let's go. FRQC uh six. And this one, I got to tell you, I had about eight, nine minutes from what I remember when I was looking at the timer. This one drove me crazy because I I looked at it. I was like, whoa, it's so long. So, it's one of those things where don't let it scare you. Look at what it's asking. quickly read it and answer the questions. Here we go. Six. The ALD gene of fruit flies encodes the ALD protein. Genes turn into protein which is associated in both the centromeirs of chromosomes and protein filaments produced during meiosis. Took some quick notes down here. In the absence of functional ALD proteins, gameamt producing cells enter anaphase 1 before homologous chromosomes are correctly aligned. As a result, these gameamtes produced will not contain the correct number of chromosomes. All right, so that's what we're looking at. It then tells you that scientists generated four mutations. We've never learned this in class. You just kind of kind of read it and and and quickly look at it and understand it. ALD13 23 and DEL which was a deletion of the gene. To study the role of ALD protein in meiosis, scientists used game forming metaphase cells from groups of flies with different ALD genotypes. Some of the flies were homozygous with a wild type al WTW homozygous while other flies were hetererozygous. So there's four of them. WCDL ALD1. Okay, so look, there's all four of them. Once again, I'm not really thinking too much about writing these down. I'm just keeping in mind that these are hetererozygous. The scientists measured the percentage of metaphase cells that contain ALD associated filaments and the amount of ALD protein produced by each of the cell types. And then it shows you this and quickly I looked at it and I looked at how it's measured the percent of metaphase cells with ALD associated filaments. Here we see WWDT that's the homozygous and these are the hetererozygous. So already in my mind I'm looking at okay hetererozygous looks higher than most of it except this one. This hetererozygous WC Dell is is showing a higher percent of benefit cells with the ALD associated microfilaments or filaments. Figure 1B showed you that look this homozygous has a bigger and it tells you right here a thicker band indicates a greater amount of ALD protein. So more protein for homozygous less about half for the hetererozygous about the same amount and then less and nothing for this ALD23 Dell. So for 6A it asks you based on figure 1A as identify the fly genotype in which the average percent of metaphase cells with ALD associated filaments is close to 12%. Here's 60% which one's close to 12%. I just take quickly took a look at it right here and here we look at fly genotype ALD1. I you don't even need to know anything about question. You just got to read a graph. Has the average amount of benefits closest to 12% in my opinion. Okay. 6B based on figure 1B describe the difference in ALD production between the game forming metaphase cells of flies with the genotype right ALD 323 flies etc. Here's my answer 6B. According to figure 1B, take a look. game forming metaphase cells of flies with genotype ALD3 23 will produce more ALD protein than flies with this. There's there's none. Okay, so that's all you need to know for B. So pretty straightforward. For C 6c, scientists hypothesize that forming metaphase cells can produce a normal amount of ALD associated filaments even when they produce about half as much ALD protein as the wild type cells produce. Use the data in figures 1 A and B to support the scientist's hypothesis. Here's my answer. 6C. According to the figure 1A, we see that WT Dell has a greater percent of ALD associated filaments than WWT. However, look over here in figure 1B, we see that it produces about a half amount of Z ALD protein. I say that this data shows that half the amount of ALD protein is actually enough to receive a normal amount of ALD associated filaments. Last one everybody 6D for gameamt forming met um forming metaphase cells of WT Dell and ALD1 Dell flies explain why the phenotypes observed in figure 1A why do they differ even though the amount of the LD protein produced does not and here is my answer for 60 the amount of ALD protein produced shown in WT Dell and ALD1 Dell flies is actually pretty similar but what we see a difference here is so here's my here's my answer but the phenotypes in figure 1A differ because of ALD1 alil most likely so something kind of kind of went wrong if you think about has a different non-coding let's just say gene than WT that will produce let's just say a lower amount of associated filaments so this one that's is what I got I could see another answer but let's just see the answer key when it comes out all right here we go thank you everybody if you watch this till the And hopefully it helps whether or not you took it already. It's already done. So don't stress about it. But if you haven't taken it, hopefully this helps your preparation. That timing, timing is huge. So go quick and make sure you practice uh this is as much as you can. As many practices as you can. I hope this is helpful for you. I wish you the best on your AP test. If you already took it, I wish you the best on your next AP test. Remember, I truly believe that you are not defined by your AP score. I truly believe that when because you challenge yourself by taking AV bio or this AB bio exam, uh you're going to learn so much from it. Even if you don't do well on the exam, you're going to learn so much. Everyone, and I really believe this, and you need to hear this, no matter what you get on this AP exam, I believe that everyone, if you keep working, if you keep having delay gratification and perseverance, you will have a great future ahead. So, keep enjoying bio and keep practicing. And this is just one test in so many in your life that you'll have many more chances if you don't do well. to reflect, grow, and continue enjoy learning. I'll see you next year. And and once again, I really enjoy taking these exams, and I hope that this was helpful to you. Thank you everybody. Have a good one.