hi it’s mr. Andersen and welcome to the final ap biology review video I asked you to submit questions and boy did you submit a lot of questions so I’m going to go through all of those I would imagine this video is going to be very long but I’ll put some links so you can jump ahead to the parts that you may be interested in and so again I asked for questions and so I got them so I got questions from 39 different states 20 different countries hundreds of District students submitted their questions and so I’m going to go through the most popular ones in this video this is a neat comment I got from one group from Belmont Belmont Massachusetts or ap bio is why so many of your videos we’d like to thank you so much you’ve helped us that on our t-shirts we are writing and I hope that’s helpful on the back thanks for all the help and so that’s a cool comment and I got tons of thank-yous and comments which make all the worth all the work worthwhile so thanks for that and so this is the table of contents what I’m going to cover in this video is number one I’m going to show you a webpage where you could go to and you could kind of find some of the answers to your questions if I don’t cover them in the video I’m then going to go through the top ten requested questions and so this starts with test strategies and goes through statistics and then finally I’m going to give you a bunch of you a good luck shoutout and so I haven’t done this in YouTube but I’m going to give it a try I should be able to insert a link here for the top ten requests and for the good luck shoutouts and so if you want to skip ahead to that then you should be able to click on that if not sorry you’re going to have to do a little bit of scrolling and so let’s talk about the website if you haven’t been to my website before that’s Bozeman science comm and I’m going to jump over there right now so this is Bozeman science comm it’s going to have different pages for the different material so if you click right here on ap biology it’s going to show you links to all of my biology videos organized in order there’s got some supplemental material here we’ve got some labs up here so you could find more information on topics that you’re interested in you could also go on the left side down here to the search and so if you have a question about operons for example you can type that in and you can find all my videos that are related to operon including the Opera one other page that I just added is this so if you go to Bozeman science comm slash review I’ve added a new page it’s kind of a hidden page and so I’ve got all of the questions that I don’t get to in the video then you could answer those here so I point you to different videos I try to answer some of the questions as best I could so if you don’t find the video your the question you’re looking for in the video you may want to go here again Bozeman science comm slash review another place to look is to go to my YouTube site so that’s youtube.com slash Bozeman biology and if you go there you can always search in the channel up here so if you click on something like up or on up here in that search box then it’s going to find all the things related to operons and that’s going to be maybe a little bit easier way to find it so whatever works for you use the website the hidden website to find information that I don’t cover in the video okay the next thing I want to do is I want to go through the top ten requested questions and so these are the burning questions the ones that a lot of people wanted more information on so sometimes thirty people would submit questions in each of these categories the first one was people wanted information on the statistics of the test like what does it consist of what are common questions things like that next test strategy is how people could improve their scores they wanted to know that followed by more information on the labs and I’ll get to that next cell communication chi-squared test and hardy-weinberg are always popular and I’ll work through a couple of sample problems next people want to know more about water potential photosynthesis respiration and finally statistics and so I’m going to work through all of these work some sample problems and then we’re done I’m going to get to the good luck shout outs and so when you take the test on Monday it’s going to be broken down into two parts part one is going to be multiple choice and grid-in questions you’re going to have 69 total questions and so those are going to be 63 multiple-choice and then the sixth grid and remember you’re going to put in numbers here and fill in the corresponding numbers below it so these are going to be ones where you use your calculator you use the formula sheet to answer them that’s going to be half of your grade on the exam you’ll have a break right here in the middle and then you’re going to 90 minutes that 90 minutes is made up of two parts you’re going to have a 10 minute period of time where you read the questions these are the essay questions they’re going to be too long form and then they’re going to be six short form essays and so on you’ll get to read the questions for about 10 minutes this is super important time where you plan out how you want to answer the questions and then you’re going to have an eighty minutes to actually write and you’ll write that in a separate booklet what do you need to bring for the exam remember pencils to do this part and bring a blue or black pen for the essays as far as test statistics I’m going to go through questions that I got from people and try to answer those number one this is from Alex from South Dakota do you think the

new and revised ap bio tests will be harder than the past test I would say this the AP biology ap biology tests are always difficult they’re designed to be hard in the sword out who really knows biology and who doesn’t and so um since they’re all curved in other words they’ll put it along a bell-shaped curve they’re going to figure out standard deviation and figure out where you’re at it’s going to be the same difficulty for everyone and so it doesn’t really matter that it’s going to be maybe harder this year or harder another year we’re still going to have about the same number of fives fours threes twos and ones it is changing in other words there’s not going to be a lot of questions that are just factual recall they’re going to be more questions where you’re actually going to have to work to find the answer or do some application or interpretation so you want to be prepared for that be ready to work especially in the multiple-choice next question is this is from Cooper from California how much is each individual section weighted for example as animals and plants worth more than genetics and ecology um they’ve kind of changed the curriculum and it’s basically centered around these four big ideas evolution free energy and this would be homeostasis information so this is going to be like DNA genetics are in here and then systems and interactions and so the questions are going to be equally divided between those four big ideas um you could go to the College Board’s website and I’ll try to put a link in the video description down below and you could look at the whole curriculum if you really have time and see where most of these questions are coming from if you’ve watched a lot of my video essentials I Center those videos around what are the important essential understandings that you should have and so if you’ve gone through the curriculum you should be ready to go next one will there be only one correct answer for the grid in and will these be computer graded or by hand that’s a good question so there will be an answer but there’s going to be a range at which your answer could be in and so for example maybe the answer is a Q value in hardy-weinberg the right answer if you did it with all the significant digits is like point three four five six the value that they would accept would be maybe between point three four and point three five and so there’s going to be a range and you can make sure that your answer is somehow in there and so it is computer graded remember the grid in sand so make sure your bubbling in those appropriately and I did find kids got into trouble if they rounded really quickly you want to kind of leave some significant digits in so you don’t get screwed up on that thanks for that question mr. Cho’s class from California next from Monica and New York what percentage of each part would you need to get correct to get a four and a five that’s really going to vary um and so depending on how hard the multiple-choice questions are in the essays I can’t tell you I would say this that it’s going to be harder than a conventional test and so if you have a test in high school biology where you’re always getting you know I consistently get an A or 80% or more or an 80% or more where 90% it’s more excuse me your 70% it’s designed to be harder than that so there’s going to be a number of questions that are very difficult and so lots of times historically if you can get you know over 70% of the questions right you’re looking at getting to four or five now that we only have four responses in the multiple choice you might have to score a little bit better than that so there’s no hard fast percent you have to get right we won’t know that until you’ve all taken the test next one Pascal from Connecticut how long should the first two response questions be um they’re going to have multi parts in them so the long ones will have part ABCD sometimes e and so they’re designed to take you quite a bit of time and so as long as you’re working through each of those sub points on average it should take you about 20 minutes to get through the long responses and the short responses are going to be more like six minutes to get through all of them and so you want to kind of keep yourself on pace what I found with my own students is that generally they’re pressed for time on the multiple-choice they’ll be pressed for time on the grid in but a lot of the time they tell me at the end everybody’s kind of done writing in the last few minutes and are not people still working on the essay and so I don’t know it’ll be up to you depending on how fast you write but I would put a lot of time and make sure you don’t skip any question Danielle from New York says what happens if you get below a three on the exam do you give up your dreams of going into the science field no away um if you’re interested in science you should study science and if it doesn’t go well for you um you might not have done a great job this year but it doesn’t mean that you can’t go into a science related field for sure um it means that you’re going to have to work you didn’t pick up the material if you fail this that you should get from a regular biology class but if you start over again are really interested in it I think you’ll do fine next Arianna from the US said could you go over any major diagrams and graphs we need to be able to read it’s a good question I don’t think I could do that because I obviously don’t know what’s going to be on the test I would tell you this that there’s going to be tons of questions where you’re going to have to do graph analysis and so just get ready for that making sure that you’re reading the labels and reading what the question is asking for it’s going to be a lot of questions we’re going to have to analyze

data and so be prepared to do that and then you’re going to have to use models and so models remember just graphical representations of a concept and so even though you might get a question where you don’t understand what this is right off the bat just kind of work your way through the model and then if you can ply some knowledge that you have you might be able to get it next one this says what math concepts could be on the exam now hopefully you’ve downloaded the formula sheet for ap biology if you just Google ap biology formula worksheet you’ll find it and it’s going to have tons of information on it so everything from the mean to standard deviation chi-squared pretty much anything on the sheet is fair game they’re going to be ones that maybe are more popular I anticipate we’re going to see some chi-squared and hardy-weinberg for sure maybe not one of the obscure ones but you never know and so you want to be able to answer any other questions on that formula sheet you’ve got a calculator and so you got to be able to use that thanks for that question crystal from California next Ellen from Washington said what is the essential difference between this year’s new exam and the previous exams and so now we’re moving into kind of strategy type questions the big thing is that ap biology used to be a mile wide and an inch deep and what that means is we covered a huge amount of material we spent you know a month just going through all the different phylum x’ and classification this diversity of life and so they’ve removed a lot of that but they want you to go into more depth and so as a result you’re going to do have to do more application of the knowledge that you have and so there aren’t going to be just questions we’re boom I can look at it and I know that’s the right answer that’s the thylakoid membrane what they want you to do is take the knowledge and then the practices of science so how we can use a model or how we can use the scientific method or experimental design to answer questions and so really you should feel a little less stress where there’s not a huge amount of material you have to know you just have to be really thorough in what you do understand next one mariya from Florida says what should we do the weekend before you can still study I mean this is a quest this is a test where if you don’t understand photosynthesis you better figure it out this weekend on the night before you really should get a good night’s sleep but Saturday Sunday you can do lots of study and figure out what you don’t know if you haven’t taken a practice exam that’s what I would do first figure out what you don’t know and then go study that how do I answer all the multiple-choice questions when they’re so long there’s so many details I get lost remember some of the questions are designed to be super hard and some are designed to be super easy and so if you get an easy question don’t overthink it if you get a hard question and you’re spending you know two minutes on a multiple-choice question I would encourage you you skip it and then the last minute go back and fill in everything and if you have to guess do so there’s no penalty for guessing and so make sure you go after it next one how should I prepare for the essay question says Rachel from Hong Kong for me this week in my class what I was working through is these what are called Direction words and so on the essays you’re going to have these questions show up quite a bit and so it’s not about the content of biology it tells you how they want you to answer the and so if you don’t know what these eight things mean explained means to make it understandable disgust means to talk about various aspects of a concept define is to give meaning described as to characterize or use words to explain it justify means to prove compare means similarities contrast means differences and if you don’t know all the good parts of a graph you may want to figure out what these words mean because some of these are what I call danger words if you see explain you’re not just going to answer that with one word or one sentence they’re looking for a number of different things you really want to make it understandable if they just say disgust that’s an open-ended question and so it’s important that you understand what these Direction words are it’s going to help you at least forming the way you want to write your essay Emma from Rhode Island says if you’re stuck on a free response question is it better leave a blank or try to write something even though it might be way off don’t worry about wrong information don’t worry about spelling don’t like restate the question there you’re not going to get points for that ap biology they want to you to write down what you know and they’re going to grade you on what you know and so lots of times you’ll have essays that are really difficult and so across the country out of ten maybe the average is three or maybe two and so if you can get any points that helps you and so I found the only time I see kids really bomb out is when they did well on the multiple-choice but they say I didn’t understand what one essay was and I just skipped it don’t ever do that battle for every point on the essays next cookie from California says do a single grit in question in a single multiple-choice count for the same absolutely and so um if you’re stuck on a really hard written question don’t spend five six minutes doing that and not answer some of the multiple-choice questions and so a grid in is worth just as much as a multiple-choice question it doesn’t mean

skip them all you should try to do all of them but it does mean don’t spend tons of time there and lose out on the other side okay next thing I want to talk about other labs there are 13 labs that you should be familiar with in ap biology I put together two videos and I’ll try to put links here for Part one and Part two these are on YouTube and you can go through and get the 13 major labs they’re not super detailed but at least they’ll give you enough information so if you’re taking the test you can answer those questions okay number four was on cell communication I’ll put together a or I have put together a video on cell communication um there’s another video I’ve done on quorum sensing and bacteria and so you may want to consult those people get nervous about cell communication it’s fairly simple if we have one cell and then we have another cell and we want to communicate between these two cells generally what we do is we send a chemical we send a chemical message and that message is going to move to another cell it might bind to a protein on the surface or it might actually move in to the cell itself and so what are some examples of this well in bacteria they’ll communicate with each other using what’s called a autoinducer and autoinducer is just a message between bacteria in us if it’s very close we’ll use what’s called a neurotransmitter between nerves if we’re talking about endocrine system we’re going to be hormones that we’re using throughout our body and sometimes like in the immune system we’re just going to use an a chemical so we’re going to just use a shape of an antigen to figure out how we communicate between cells and so again I would encourage you to watch the video on cell communication if you’re stuck on that um but it’s really just a way that cells communicate with one another okay next thing I want to do is I want to go over some chi-squared problems and so this is one that gives gives a lot of students fits and so this is the one that I gave to my students on their AP exam so this is their final so in pea plants the purple allele is dominant to the white allele Gregor Mendel performed a cross between two purple flowers pea plants when planted the 236 TS that were produced from the cross matured into 164 plants 72 plants with white flowers calculate the chi-squared so we know it’s a chi-squared value kind of question for the null hypothesis and so for me if I’m ever trying to answer a genetics question the first thing is I want to talk about what I’ve been given and so they say here that the purple allele is dominant and so what I would write is big P equals purple and then what else did they tell me it’s dominant to the white allele and so little P is going to equal white so I know that what else have they told me well they telling me that the parents were both purple and that they were heterozygous okay so that means I’m going to have to do some kind of a punnett square I’ll get to that in just a second but this is a chi-squared and so a chi-squared you know it’s generally a chi-squared if they give you values and so they’re telling me that the number of purple plants were 164 the number that were white were 72 and this is the total 236 so in general for me when I’m doing a chi-squared test I like to organize it like this I write down the observed values and I’m going to write those across so our observed values we had 164 of the purple and then we had 72 of the white and so what I have to do is figure out the expected values expected values we’re going to have to use a Punnett square to predict that and so they’re saying that the parents were both heterozygous and so I’m going to just write out a Punnett Square for those parents and so that is big P little P and that’s going to be crossed with big P little P and so I’m going to write this one is B big P big P this one’s going to be big P loop this one’s going to be big P little P and this is going to be a little piggy little P okay so what would Mendel predict Mendel would predict that these three one two three are all going to be purple and then how many are going to be white just one of four and so another way to say that is it’d be around 70% 75% excuse me or three-fourths are going to be purple and 25% are going to be white okay so now I got to figure out my expected values there’s a total of 236 seeds and so what I can do is I can take 236 times 0.75 and if I do that on my calculator let me grab my calculator for a second so I’m going to take 236 times 0.75 and I get 177 and so how many if Mendel’s right my expected value here should be 177 now let me figure out my expected values over here so we could say this is white and this is going to be purple over here and so how do I figure that out well my total again is 236 this time I could take it times 0.25 because that’s going

to be how many are white and so if I take 236 times 0.25 I get 59 and so what is the chi-squared chi-square test is going to be way up here and so chi-squared test this is just the symbol for chi-squared but it’s going to be the summation of o minus e squared over e and so now that I have all of my o’s and a lined up it’s really easy to solve this problem and so I’m going to write my observed value so my observed values is going to be 164 minus 177 and I’m going to square that and that whole thing is going to be over my expected values which is 177 I have to do that for my other side as well and so I have to do that for the whites now and so that’s going to be my observed value which is going to be 72 minus 59 I’m going to square that and then I’m going to put that over my expected value which is now 59 and so if I do this kind of in my head 164 minus 177 is negative 13 if I square that that’s 169 over 177 and so if I do that in my calculator 169 divided by 177 and I get 0.945 4 so for this first one I get point 9 5 4 so that’s going to be for the purple flowers that’s going to be my chi-squared value now I’m going to do my white ones over here so that’s plus so this is going to be 7 as you minus 19 so that’s going to be 13 squared again so that’s 169 this time it’s over 59 and so I’m going to take 169 divided by 59 and I get two point eight six so two point eight six and that’s plus 0.945 for and so I get three point eight one and so what is my chi-square value it’s going to be three point eight one okay so what does that mean well let’s look at how many degrees of freedom that we have and so how many degrees of freedom do we have well there are two different phenotypes we’ve got the purple phenotype and then we’ve got the white phenotype and so how many degrees of freedom and are going to have I’m just going to have one degree of freedom so that’s going to be in this column and how do I get one degree of freedom it’s n minus 1 where n is the number of different types I have so I have purple and white and it’s going to be minus 1 so it’s going to be 1 is going to be my degrees of freedom and so what’s my critical value 3 point 8 4 and so we’re really close to that but we haven’t exceeded our critical value and so we’d still have to accept our null hypothesis and so we could say that Mendel’s right that this is predictive at least in this quick hardy-weinberg okay let’s go to chi-squared so this is again the same one I asked on my final and so what do we got here or it’s like a 1 I asked to my final so in a population of snakes the allele for brown skin is dominant to the allele for an invasive huh hawk targets the red skin snakes when the hawk is removed only 8% of the remaining snakes are red and so in hardy-weinberg what I like to write out is the whole thing so this is P squared plus 2pq plus q squared equals 1 and then what’s the other part of that it’s going to be P plus Q equals 1 and so what do I know well I know that the brown so I’m going to say Brown is going to be dominant and then little B is going to be red so that’s going to be recessive and so what did they tell us well they told us when the hawk is removed 8 percent of the individuals are red and so this is where I pause I mean if they told you Q have they told you P P squared Q squared what have they told you well in almost every one of these problems they’re pretty predictive is it’s going to tell you Q squared because these snakes we know what their genotype is we know that they have both of those red recessive alleles and so they’re telling me Q squared so Q squared equals I want to make sure that I write this not as a percent eight percent but I write it as a decimal value so that’s going to be point O eight and now I can solve for my Q value my Q value is going to be 0.08 and I’m going to take the square root of that and what do I get I get 0.28 – so that’s going to be 0.28 – and once you get Q you should immediately figure out P and so what’s my p value going to be it’s just going to be 1 minus 0.2 a 2 and that’s going to be 0.718 okay so now I have P and Q once you have P and Q you can answer almost any question so what are they asking for so if this is in hardy-weinberg what will the frequency of the brown-skinned allele be for the next generation well we’ve already figured that out that’s going to be right here so that’s going to be 0.718 and since they’re Lasky asking for an allele frequency we should just leave it as a decimal value and then they say if a thousand snakes are in the next generation how many brown-skinned snakes will be heterozygous well now we’re going to use this right here which is

going to be two PQ so we’re going to take two times P which is going to be 0.718 and then we’re going to take that times Q and Q is going to be 0.28 – and so if I do that let me use my calculator so I get point 404 or point 405 actually 0.40 five okay so that’s going to tell me the decimal or the percent of individuals that are going to be heterozygous so how many are they asking for a thousand snakes and so if I took a thousand times point four zero five what I’m going to get is around four hundred and five snakes so four hundred and five of the brown snakes are going to be heterozygous and so again for hardy-weinberg I would always write out the equations right what you’re given and then generally they’re going to have to give you one of two things they’re going to have to give you the Q squared value because you know the genotype of those or they might just straight-up give you the allele frequencies and then it’s going to be a little bit easier to solve that question okay next one next one’s going to be on water potential and this is really common question I’ve got in class as well so water potential is a little confusing and I think the symbols are somewhat scary oops let me go back to that and so on on this one what we’re looking at is sigh and side is equal to two things it’s going to be equal to the pressure potential plus the solute potential and don’t worry these are all written written on the formula sheet and so what does that mean the overall water potential is going to be it’s actually based on many other things but it’s the pressure potential and the solute potential and so what does that mean well let’s make a little beaker here and so we’ve got a beaker that’s filled let’s say with distilled water so we got distilled water in it and then let’s put a cell on the inside okay so this is distilled water out here what’s the water potential of distilled water it’s always zero so that’s going to be zero but let’s say we have a cell here and this has some solutes in it so it has some stuff in it and so if we ever add stuff inside a cell that’s going to take the solute potential and it’s going to drop it and so it’s going to be a negative value and we’ll get to why in just a second and so what happens well if you look out here the water potential is going to be zero if you look inside the cell what’s going to be the water potential it’s less than zero so think of water potential the way I think of it as as the potential energy of water like where is there a lot of water there’s going to be way more water out here than there is in the cell and so where is water going to flow it’s going to flow inside and so it’s flowing always towards a low or water potential and so since there’s still a difference in water potential water’s going to keep flowing in and waters going to keep flowing in and what’s going to happen to the cell it’s going to get bigger and bigger if this is a human cell it might lyse but let’s say it’s a plant cell what does a plant cell that have that a human cell doesn’t it’s going to have a cell wall around the outside and so as water starts to flow in it’s just like a balloon as it starts to fill up the balloons going to start to exert a pressure and it’s going to try to push that water out of there that’s the pressure potential so solute potential is always going to be zero or a negative value pressure potential is always going to be a positive value and so that’s trying to push the water back out so eventually what happens is it’s going to reach a balance in a plant cell and so waters you know still trying to flow in but the pressure is pushing some of that water back out and so that’s going to be overall water potential why is this important well it’s really important so if we look at a tree a tree is going to have roots and those roots down here are going to have stuff in it and so what is the water potential well the water potential outside is going to be closer to zero it’s going to be close to distilled water but it’s going to be much lower here and so where’s the water going to flow it’s going to flow in here it’s going to go through the xylem it’s going to work its way up to the leaves and eventually it’s going to evaporate off the leaves and so where’s the lowest water potential lowest water potential is going to be right here whereas the highest water potential right here and since trees lack a true circulatory system it’s just water potential that’s getting up to the top now one other thing I should mention with that is how do we calculate solute potential solute potential is negative I see our t and so what does that mean well that’s always a negative value and so if I were to draw a cell down here let’s work through the thing so first of all C is going to be concentration and so the more stuff I put in the cell the more concentrated it is that’s going to increase this concentration what’s that going to do the solute potential is going to move it down since this is a negative value so again by adding more stuff that’s going to increase concentration and it’s going to decrease the solute potential this R is a constant value and so it’s not going to change I’m not going to worry about that right now it’s written right on your sheet what is T T is equal to temperature but it’s going to be in Kelvin so you’ll have to take remember the number of

degrees Celsius plus 273 to figure it out but again if we increase the temperature as the molecules are moving around in here more quickly there’s more area for water to move in and so again if we increase temperature what happens to our solute potential it goes down even more since it’s a negative value and so that’s going to allow more water to move in here what’s the last thing we haven’t talked about I I is going to be the ionization constant and so what does that mean well what does it mean to ionize if I take sugar so if I say let’s just take some glucose c6h12o6 and i put that in water it’s going to stay together as this sugar molecule is this hexagon and so it’s just going to dissolve in the water but if I take something like sodium chloride so if I take salt and I put that in water it’s going to quickly break apart into sodium ions and chloride ions and so what we’ve really done here is double the stuff that we’re putting inside the cell and so if you ever have salt the ionization constant is going to be two and if you ever have sugar the ionization constant is going to be one and so what happens if we add these ions again that’s increasing the ionization constant and that’s going to decrease solute and so again the equations are kind of scary but as long as you know that as solute potential goes down water wants to flow in more and then you just know how to solve the problems it’s really not that scary okay next one then is going to be on the free energy kind of and so this is the photosynthesis and respiration so free energy remember is equal to Delta G and so Delta G is the change in free energy and so if we were to put free energy on this side so if we put free energy like this these are the reactants and then these are the products and if I were to show you a little diagram like this and this is time going across so this would be like respiration so our reactants have higher energy than our products and so this is an exergonic reaction if we were to let me try a different color so if we were to do a different color here and do photosynthesis it’s going to start with a lower and then it’s going to end up with higher potential and so this would be an endergonic reaction or a positive Delta G and then this run right here would be a negative Delta G but a common question I got was could you talk about coupled reactions well sure it’s this right here you should be able to identify these equations if you don’t know it please learn these and so this is going to be glucose plus oxygen makes carbon dioxide water and energy this is going to be cellular respiration right here and so this is going to be an exergonic reaction and so what we’re doing is we’re releasing the energy that’s found in the glucose and we’re tying that to the formation of ATP and so this is going to be up here an exergonic reaction and we’re coupling that with an endergonic reaction here and so where is this energy going that energy is going to make ATP and so likewise um what’s this down here this is photosynthesis so we’re storing energy in the glucose and then we can eventually use that glucose if we’re talking about a plant to do respiration or we can eat the plant and we can do respiration on that and so it’s really important that you understand that the free energy in our planet is all coming from the Sun and we can use that free energy or we can convert it into another for okay so another common question I got was photosynthesis could you go through the steps of that and I sure would love to photosynthesis is made up of two parts we’ve got the photo part and the synthesis part photo always stands for light and then synthesis stands for the making and so this over here is going to be the Calvin cycle so it’s named after melvin calvin and so what I’m going to draw down here is a chloroplast and so chloroplast is going to have two parts to it it’s going to have a thylakoid membrane over on this side and then over here it’s going to have what’s called the Calvin cycle this takes place out here in the thylakoid these are going to be the stacks inside this chloroplast and this out here is called the stroma and so what’s going on in the light reaction well we need light and so light is going to come in and it’s going to strike a photosystem that’s going to be in here in the loyd membrane what is it using that energy to do it’s using that energy to first of all I’ll be passed down an electron transport chain so if I were to draw that what does it look like we have this photosystem right here and so this is the light coming in and so what that’s going to do is get electrons excited and its eventually going to pass electrons down an electron transport chain and so what does that mean as they’re moving down this gradient it’s going to end up pumping H+ ions to the inside and so this over here is called photosystem two and that’s because it was discovered second what happens to the electrons well the electrons as they move through this they’re going to pump protons to the inside and then it’s eventually going to go to photosystem one what does photosystem one going to do it’s going to take that energy and it’s eventually going to create what’s called NADPH and so NADPH is carrying

electrons to the Calvin cycle it’s going to be one of the things that’s going to be created in the light reaction so this is NADPH what is the other thing that’s created in the light reaction well let’s keep watching that so as this moves down we’re going to pump protons to the inside so we get more H+ more H+ and what eventually happens and I’m running out of space here on my diagram is that eventually that’s going to run through an enzyme called ATP synthase and so as the protons run through here that’s going to generate ATP and so ATP and NADPH are the two things that are made in the light reaction now where are the electrons coming from the electrons are actually being donated by the water and so the water the h2o is donating its electrons for the electron transport chain what is it producing well the protons are going to be the ones that move through the gradient and then finally we’ve got oxygen and that oh two is the oxygen that you’re breathing in right now so in the light reaction remember what are the big things we need we need a little bit of light what else do we need we need h2o and what are we going to produce we’re going to produce on oxygen that’s the oxygen you’re breathing right now what’s over here well this is the Calvin cycle and so in the calvin cycle what are we taking in we’re taking in carbon dioxide’s not carbon dioxide in the calvin cycle is eventually going to be used to make something called g 3-p it’s a three carbon molecule it’s got high energy where’s the energy coming from it’s coming from the ATP and the NADPH what happens when they’ve dropped off their energy they’re headed back to the light reaction so this is photosynthesis again this is going to take place in plants and other producers and and we can’t do it and so that’s how they make g3p and eventually they can use it to make sugar so we don’t do that but we do cellular respiration so what is cellular respiration cellular respiration let me quickly draw a chloroplast excuse me a mitochondria and so this is going to be a mitochondria so what are the three steps of cellular respiration well the first step is going to be called glycolysis what happens in glycolysis we’re going to take in glucose which is a six carbon molecule and we’re going to break it down into two molecules of pyruvate okay so these are three carbon molecules as we do that as we go from one six carbon to two three carbon molecules like this starting with a six remember what we’re doing is we’re releasing some of the energy that’s locked in that glucose and so we’re going to make a little bit of ATP here just to make two net ATP’s at this point so where’s the energy going well the energy at this point has been converted into something called NADH and so what is it nad doing its carrying electrons and it’s eventually carrying electrons to the electron transport chain so what happens to that Puru Veit that prove it is going to diffuse in through the membranes of the mitochondria into what’s called the matrix it then becomes asset Ile coa and then it enters into what’s called the krebs cycle the krebs cycle don’t confuse it with the calvin cycle but what’s happening is that asset ile coa as it goes into the Krebs cycle is eventually going to convert these carbons down into carbon dioxide so we’re going to make co2 so that co2 and our atmosphere is coming right here from this Krebs cycle what do we create in here we create a little more ATP so we’re going to make two ATP what else do we do we’re going to send that energy from the Krebs cycle that’s going to go to nad NADH and it’s going to also go to fad what are they carrying they’re carrying high-energy electrons to the electron transport chain so this is the last step right here what happens in the electron transport chain those electrons from that and fad are going to be used to pump protons to the outside of that membrane this looks a lot like photosynthesis and as these things flow back in through ATP synthase we’re going to make a bunch of ATP so how much ATP do we make here sometimes 32 sometimes 34 ATP and so we’re going to make a whole bunch of ATP at the end and that’s because we’re harnessing all the power that was found in that glucose molecule what I’ve just described is aerobic respiration um what’s the aerobic part well the oxygen so the oxygen at this last point is going to be the electron acceptor so as those electrons from that and fad go through the electron transport chain they eventually will be accepted by oxygen and what’s that going to create it creates something called water and so understanding where the reactants are on the products are so where’s the glucose that’s our food what else do we need for cellular respiration we need oxygen and what does that oxygen do it’s the final electron acceptor what are we making in cellular respiration again we’re making water what else are we making carbon dioxide coming from the krebs cycle and then we’re making energy in the form of ATP okay last one then is on statistics and so a question I kept getting was um you know what kind of questions could they ask us in relation to statistics and the right answer is they could ask you anything and so they could ask you to do standard air they could ask you to do standard deviation I’m not thinking that they’ll give you a bunch of questions in standard deviation because this takes a while but you should know

conceptually what it is they could ask you to do the mean I hope you know what that it means that’s just the average and then they could ask you to do chi-squared so they could ask you to do anything here some things that sometimes trip up my students they forget what n is so n is going to be the size of the sample and so if I have to say here’s the data I’ve got ten nine point two and eight point eight three point three and four point nine and ten point one so if these are my data that I’ve collected how would I figure out the mean well I would figure out the mean by simply adding all those up and dividing by the number that I have here and that number that I have here is going to be equal to the ants that’s the size of the sample and so if you want to figure out you know standard deviation what you’re going to do is you’re figure out the mean and then you’re going to find the average distance from the mean we square that and it’s going to be over n minus 1 take the school whole square root of that I think that’s going to take a long time to do that and so I don’t anticipating them giving you a question like that but you never know okay that was quite a review and so I hope it was helpful to you and if you skipped over that that’s probably good sign it means you’re ready for the AP exam one thing I did on my form is I asked you if you want me to wish you good luck on the exam just check a box and I would love to wish you good luck and so that ended up being a lot of people and so we’re going to go through this list it’s going to take me a little bit of time but I really appreciate all of the thoughtfulness you put into your comments thanks for that and I want to give you a good luck wish I want you to do well on the exam so really best of luck so let’s start with Alabama from Alabama we had Joey and Lila good luck on the exam I hope you do well from Arizona we had Tyler mrs. Thomas’s ap bio class Nico Sacha Maryvale high school ap bio class Fran Matthew and Vita Jesse Aaron and Michelle and Shiv and Kevin congratulations on finishing the class good luck Arizona in Arkansas we had McKenna and Miss wallchuck ap bio class good luck in from California we had Allen in Andrew and Angelica amelia Elizabeth eisah Donald Deanna we also had Dante Danny Cooper Clarissa Cynthia Marin Catholic ap bio class Kristina Christian Bradley Ashley also Ariana and Victoria annum Ileana Hannah also good luck to grace Esther Emma Righetti ap bio class crystal Krish Kevin who else Kelly from California Katie kaki juju Joseph and Jonathan Jimmy from California Jennifer from California Jai he ISA Miss Schlegel’s ap bio class from California mr. didn’t xapi bio class and mr. bucks ap bio class also good luck to Mia and me and also Matthew and Mary Ann and Mark and Li Lin limey and also Leona in Savannah and Sarah also good luck to Roxy and Renata also good luck to Rachel Oscar and Noir good luck to Naida miss Johnson’s ap bio class miss Churchill’s ap bio class Nicanor also miss bricks AP bio classes Zeinab and Stephanie Z good luck yeahshe also to Wendy good luck and Tiffany good luck also to Thomas Terrence talbin Sarah Samia so that was a lot of folks from California I hope your state does well on the AP exam from Colorado good luck – Alex Kelsey Kelly Sonya saniana Brad Sarah and also Ephram good luck – Fran as well from Colorado and Connecticut please good luck – Mis bolas YZ ap bio class – Jasmine Carolyn ank Lauren Eliza Tyler Kate Isabella Darwin’s finches sounds really cool dan also good luck – dr. DS ap bio class Jade and Pasquale next in Delaware good luck – Mike a ly ly Sri nian Frank and Adam from Florida good luck – shreddy Rachel Kaitlyn Jacqueline also Marian Elizabeth Gabi and Sarah good luck – Meghan Maria Julie aakriti Lauren Carrie and Carly Ellie good luck Jordan Joshua sigell Emily Veronica mr. McMasters ap bio class – Joey good luck Parker and miss Malone’s ap bio class also – desperate help good luck Hillary abigail Kwan and in Austin wow that’s a lot of people from Florida good luck as a state in Georgia good luck – Jin Harley Josiah Zara is Dane and Mike from the great state of Georgia from Illinois good luck – Cameron Lydia and Kavita from Indiana good luck to

bill and south mount high AP bio class good luck to Dan and Rachel and Cora in Iowa good luck – Nancy Sarah Tim and Tim in Kentucky good luck – Sabrina Jackie Kevin Sarah miss Smith’s ap bio class into the Henderson County ap bio class good luck from Maine good luck to Kate and Hannah in Maryland good luck to Amanda Jules Jack and mr Mazzella Sierra Tim Ashton Matt Chandler Brody Brandon and Molly good luck to Kiki mr. Scott’s ap bio class Sahana Chico and jemima also in Massachusetts good luck – mr. dope mrs. Doyle’s ap bio class mrs. Tom’s ap bio class mrs logics ap bio class – Stephen mr. Walsh ap bio class Megan also good luck to Maddy and lavender and Lauren and Kennedy and Miss Renner’s ap bio class good luck Julia Heather and Ellen and also too breasty Jared Philippine Monica TM harem and Russell also good luck to Ashlee Belmont AP bio class and finally Abigail in Michigan good luck to Israel and also Duras Alex Kayla Mike Brandon high school AP bio class – Haley good luck Harris Karuna ap bio class Mohammad Piper and Annie Kevin good luck naminé Raymond Ricardo and Sarah from the great state of Michigan luck Minnesota good luck to Thomas Abel Abel probably Martha and Lilly in Missouri good luck to mrs Ketchum’s ap bio class and – Lakshmi next in Montana good luck to mrs. peas ap bio class – Nina and mr. Anderson’s ap bio class good luck guys I hope you do well on Monday Nevada good luck – Marysol Jocelyn and Cosette in New Hampshire good luck to mrs. Grimsley’s ap bio class in New Jersey good luck to Burrell also – Erica Amell Barbie re Nicole and Rajani – Danielle good luck Jennifer Rachel Kate in New York good luck – Amanda and Damion – Dylan – Chloe – Abby – Alisa – Amira – Brandon – Aang – Christopher maybe that’s Angie – just until a towel – miss Rogers ap bio class good luck – ro eat – Rosie – Yael – Louie – Kyle – kusuma – Liam – Lewin – Highland – Emily – Aaron – fazil – Danielle good luck – Damien em – davidandamy – Julie and John and loyal ap bio class – Ikki – Ikey – jack – sky – Amanda – Tiffany – Victoria good luck – spongebob – Corrine Brennan and Jared – Emily Alex L Alexa Chloe Peter Megan Danny and PJ also good luck – mrs. DS mr. D’s ap bio class good luck – miss slummin Nikki’s slum Nikki’s AP bio class and – nyami and also good luck to Sid and Sarah Riki and Monika a lot of people in New York good luck guys in North Carolina good luck to Matthew and Desmond ray also good luck to autumn – Todd korok jasmine Erica Kendra Ashley Taylor Victoria Mackenzie and Meredith good luck to hewan and Heidi – miss Hinson’s AP bio class – Jake and panty yota – Joshua – hailey – Regan and Jess in Ohio good luck to mrs. mr. bun PSA’s ap bio class – Alisa – miss Abrams ap bio class – Tiffin Columbian biology class or club Wow – Nate – Laura and Ashley Courtney and Rachel good luck to Drew in Oklahoma good luck to auxin and Lodi in Oregon good luck to Reese in Pennsylvania good luck – Kay so Carolyn Ryan and Michael in Rhode Island good luck to Emma and Victoria in South Carolina good luck to Shashank Sasha Inc and the SHS ap bio class in South Dakota – miss Rydell’s ap bio class and – Alex in Texas good luck to John and Emma and ibrahim be Bream Ebru my think that’s right – Christy – Daisy – Hill County Christian AP bio class good luck to Amy and Alexander ed Shweta and Becca and sunny and Caroline and miss Reed ease mr. Reed’s ap bio class and mrs. rice AP bio class in Rowan and Ruby and mrs. Abney’s AP bio class from the great state of Texas good luck guys in Utah good luck to Jionni and mark and mr. della dukes ap bio class good luck in Virginia – Neil and Sydney and Ashley and Annie in Washington – Jude and grace and Michaela and Sarah and mrs. left stats ap bio class – Kyle and Allen and Julia in West Virginia good luck – Jason in Wisconsin good luck – and jela and Katie and Sarah and Nicole and Sri and Alex now we’re going to the countries in Austria good luck – Gaede and in Canada Tatia and Sam and Celina and nude rot and Massoud and

Lyndon and Cathy and Jessica from Hong Kong good luck to Rachel in India good luck to Rapala in Italy good luck to Santiago and Jamaica good luck to zacchara in Mexico good luck tabria and Natalie and in the Netherlands good luck to Molly and in Pakistan good luck to Farouk and in Puerto Rico good luck to Alexis in Saipan good luck to Ashley and in Saudi Arabia good luck – wha and South Korea good luck to Allison and in Switzerland good luck – Marcos and in Taiwan good luck to Monica Thailand good luck to Sally and Trinidad good luck to miss Donovan’s ap bio class and in the United Arab Emirates good luck to Ryan and Mohammed and in United Kingdom good luck to FA and high thumb in the US good luck to Kiran and hope and Joshua and Katie and coral and Kelley and Ariana and Bella and Albert and Jenna and Marah Marah and Michelle and Tyler and Peter and Nikhil and will and Yanni and Tina and Samir and Ralph and Jimmy and Harry in Venezuela good luck to Camilla Wow I’m done so good luck to all of you I hope you do really well on the AP exam I hope that all the videos have been helpful my voice is gone I’m tired and so good luck to everyone and I hope all of this was helpful