all right you guys we are gang started with chapter 9 it is some I would say probably the least favorite chapter of all of my students when I asked them which one did which chapter do you not enjoy well they would pick this one so chapter 9 is deals with how energy is made by you cells so when I think of energy in cells I think of adenosine triphosphate which is a P P all cells need to produce energy in the form of ATP and we're gonna see that there are two different ways of producing ATP there is cellular respiration and that's depicted on the left hand side of the slide and then there's fermentation which is on the right hand side so cellular respiration has four stages with they are glycolysis pyruvate oxidation citric acid cycle which is also known as the Krebs cycle so be aware on your exam you see citric acid cycle it's also the Krebs cycle and it's also the TCA cycle and then the last stage of cellular respiration is the electron transport chain or as we just shorten it to ET see now when you want to make energy cellular respiration will make a lot more energy than fermentation well fermentation takes place without oxygen and the only stage that we have is glycolysis there is no dtc and the significance of that is that most of the ATP is made in the electron transport chain so the fact that it's missing in fermentation is huge we're gonna see that in glycolysis we're gonna have electron acceptors that are other things other than oxygen these are organic molecules other than oxygen so of course all life requires energy energy in your cells is in the form of ATP and what we're going to do is we're going to oxidize glucose so as I like to think of it we're gonna steal energy from glucose when we're stealing energy from glucose we're oxidizing glucose so something that has a lot of energy is highly reduced so glucose is highly reduced we want to steal the energy in glucose it make a pee-pee with it so we're going to oxidize glucose if you pay close attention to the slides you will see the word oxidized oxidized oxidized and so in my mind I just think oxidation is stealing energy from something that has a lot of energy something that is highly reduced like glucose so they tell you that cells are constantly having to make ATP because if your cells stop making ATP we would be alive for no more than three minutes ATP is unstable cannot be stored so cells have to make it all the time and what cells love to use in order to make ATP is glucose so where do we get our glucose from well we get it from the plants that we ingest maybe had brussel sprouts for dinner that was a plant maybe you have lettuce that's a plant and plants produce glucose during photosynthesis which is by the way the next chapter so we obtain our glucose from food that's why we have food so that we can obtain our nutrients and then of course we don't want to run out of energy something that we can use to oxidize this so we can steal its energy so we store our glucose as glycogen so you and I are animals so we store our excess glucose in the form of glycogen we're gonna find out that that's stored in our muscles and in our liver and then starch if you're a plant you're going to start your store your excess glucose in the form of starch so think of potatoes which are very starchy that's the excess glucose that is being stored by the plant so when it grows it has it available here is the equation for cellular respiration again we're going to take something that has highly reduced has a lots of energy that is glucose and we're going to oxidize that we're gonna steal its energy and the process they tell you we're gonna need the presence of oxygen so that's the gas you inhale you know that's what you breathe in and the process you're gonna produce co2 in fact notice that there are six carbons in glucose and there are six carbons and co2 and that's for a good reason all the carbons that were originally in glucose are going to be released as co2 you're exhaling it when you breathe out co2 and then you're also going to produce water and heat and light or a source I think of energy in the form of ATP so yes cells oxidize glucose they steal its energy in a series of redox reactions remember that redox stands for re for reduction what is reduction you better know that that's super-important reduction is the gain of electrons and the gain of energy and the gain of hydrogen's oxidation is the opposite oxidation is the loss of electrons the loss of hydrogen's and the loss of energy so yes we're taking glucose we're going to steal the energy in glucose and we're gonna synthesize ATP with it and there are four stages to cellular respiration and yes you must know all the four stages we're gonna see that fermentation is another way that we can get ATP and I shouldn't say wheat there are some cells in your body that can perform fermentation but we perform cellular respiration so fermentation will us also oxidize glucose steal the energy and glucose in order to make ATP but because we don't oxidize glucose fully we're not going to produce as much ATP as we can with cellular respiration in fact with cellular respiration we get around 36 to 38 ATP's per glucose what about fermentation to two ATP with fermentation so yes solution is the way to go if you want to produce a lot of energy in the form of ATP what they're showing you in this slide is that in photosynthesis and notice that these are the opposite reactions to each other if you take the equation for cellular respiration and compare it to the equation for photosynthesis they're the opposite of each other in photosynthesis photosynthetic organisms like plant plants take the co2 in the atmosphere and they reduce they reduce the co2 make carbohydrates like glucose and they meet water for this as well as energy in the form of sunlight not energy in the form of ATP but energy in the form of sunlight so photosynthetic organisms are able to convert the energy in sunlight to the energy that's stored in bonds of molecules like glucose all right and then here we are looks like we're in a big rowing race we need energy in the form of ATP so we take that glucose maybe we had a nice meal with lots of carrots um maybe you carb loaded maybe you had pasta lots of sugars you oxidize those carbohydrates in the presence of oxygen and with adenosine diphosphate and inorganic phosphate you produce co2 again that's the gas you're exhaling water and most importantly ATP because you would not be alive for more than three minutes if your cells stopped making energy in the form of ATP fermentation you start off with glucose adenosine diphosphate and inorganic phosphate no oxygen needed and you produce small organic molecules like lactic acid ethanol and ATP but as I said far less ATP is produced via fermentation as opposed to cellular respiration you only get two ATP with fermentation now this is I think why students have a hard time with this chapter you have to do a lot of memorization you have to know what the stages are and you need to know what goes in and what comes out at each stage so what I say is if you know what comes out then you can work backwards and discern what goes in so for example if ATP is produced then I know that ADP and inorganic phosphate must have gone in all right so yes you do need to keep track of what goes in and what comes out so first stage of cellular respiration is glycolysis where we produce two 3-carbon pyruvate molecules and yes you have to know exactly how much of each product is produced in fact let me give it all to you at once in glycolysis you produced two pyruvate to NADH and two ATP net by the way yes you definitely have to know that we're gonna see that that's what they tell you with all the slides but I can already tell you yes you do have to know what are the products of each of the stages to cellular respiration again in glycolysis I produce two pyruvate to NADH and two ATP net and pyruvate processing I produce two acetyl co a I'm going to produce two NADH and I'm going to produce two co2 do I do you have to know that absolutely citric acid cycle also known as the Krebs cycle you produce acetyl co a goes in you produce six NADH to fadh2 for co2 and two ATP or GTP yes you have to know what the products are and in the electron transport chain or the et Cie we produce the most ATP and you guys this is an exam question you have to know during which stages ATP is produced and if you if you wrote down what I was saying you would say well I produced like ATP and glycolysis I produced ATP in the citric acid cycle also known as the Krebs cycle and I produce a lot more ATP in the etc' in fact you produce the most ATP in the etc' and I think you better know that for the exam and in any of the stages where you produce ATP you have to know how its produced you have to know how its produced so for example in glycolysis and in the citric acid cycle you produce ATP and it's via a process known as substrate level phosphorylation in the last step which is the electron transport chain you produce the most ATP via a different process known as oxidative phosphorylation and yes an exam question will require you to know in which stages you produce ATP and how all right so please don't forget okay moving on to the next slide here are the four stages that we just talked about the first stage is glycolysis and notice what they're showing you yes you have to know what goes in and what comes out and if you know it comes out that you can go and work backwards and say well then I know it goes in so they're giving you the information in pieces small pieces at a time I'm giving you all the information at once because we have to know it all first stage of glycolysis what goes in glucose what comes out what are my products to pyruvate to NADH and to ATP net and the net is important because you produce for ATP but you actually have to use 2 so 4 minus 2 is 2 ATP net next stage is pyruvate processing what happens there pyruvate goes in what comes out to NADH to acetyl co a and to CO 2 next stage is the citric acid cycle also known as the Krebs cycle also known as the TCA cycle what goes in acetyl co a what comes out 6 NADH to fadh2 for co2 and 2 ATP or GTP GTP similar to ATP and the last stage is the electron transport chain or the et Cie and what you need to know about that is that this is where you produce the most ATP and then I forgot to tell you you also need to know where these different steps take place in a eukaryotic cell so glycolysis takes place in the cytosol and you see that they're telling you in that figure the next two stage is pyruvate processing citric acid cycle Krebs cycle they play they take place in the mitochondrial matrix and then the last stage in a eukaryotic cell takes place in the inner mitochondrial membrane and then there's something else you have to know I'm hitting you with everything you need to know if ATP is made you need to know how that ATP is made so in glycolysis and the Terk acid cycle ATP is maybe a substrate level phosphorylation and in the EPC ATP is made in a different way via oxidative phosphorylation and other than that there's a lot of slides but that's really the the meat of it what you must know so yes in cellular respiration we have four sets of reactions we take something that's very energy rich something that's highly reduced that's glucose and we use that energy to make ATP because guess what cells need an energy source to produce ATP and then if you're an organism we also need to worry about your source for carbon so if I need to make these macromolecules like proteins polysaccharides etc I need to worry about what am I going to use to to make my carbon molecules they tell you that we have catabolic pathways and anabolic pathways with catabolic pathways I know that they break down molecules and they release energy in the form of ATP whereas anabolic pathways are the opposite here think of somebody who's taking anabolic steroids they want to get bigger right so here you're building larger molecules and then you need energy in the form of ATP so they tell you that when it comes to ATP production cells will use whatever they must in order to produce energy in the form of ATP the preferred energy source are carbohydrates like glucose but then after that if there are no carbohydrates around yourself will go after fats there are no fats around cells will go after proteins so as cells a cell needs to worry about how am I gonna make my energy in the form of ATP it will utilize what it has to and this is the idea for loaf low carb diets so the idea is that you limit your carbohydrate intake because then your cells are gonna say well there are no carbohydrates around so what am I gonna go after next fat's well most of us most of us have plenty of fat and so we want to lose that fat so low carbs low carb diets to make a lot of sense although man you're gonna be miserable with no carbs alright and then let's say there are no fats around no carbohydrates what's it still gonna go after whatever it has two proteins and this is dangerous because hey it's in your heart a muscle made of protein absolutely alright so they tell you that okay I'm gonna skip these slides if I skip the slice they will not be on the exam so I'm gonna skip this one I am going to skip this one and then this slide is just telling you what I just said cells will use whatever they have to in order to produce ATP carbohydrates are the preferred source like glucose after that your cells are going to target fats and then after that proteins will be targeted and that's all I'm gonna say about this slide they tell you metabolism is all the chemical reactions that take place in a cell and they tell you that cells want to maintain homeostasis so these stable conditions so for example where do I want to maintain homeostasis well I want a stable body temperature don't you don't we freak out when we have fevers absolutely you want to have stable blood blood glucose levels don't you absolutely so for that reason we have all of these metabolic pathways that ensure that we maintain homeostasis as much as possible and even though in your book we have a bunch of chemical reactions and it's like a leads to B and an arrow from B to C in reality when it comes to metabolism man it's all of these different reactions that are all intertwined interconnected so again they're telling you what I already said for cellular respiration to worry about what goes in what comes out if I know what comes out I can work backwards and say well I know what came in you need to know what happens to the energy that's released where does each step up occur we already talked about that where does glycolysis take place in the cytoplasm in every single stage you better bet has to be regulated so they tell you that hmm I'm gonna skip this slide I mean it's interesting it's the history of glycolysis but we have plenty to memorize already so glycolysis actually it consists of ten chemical reactions but I'm not gonna hold you responsible for knowing each of the ten steps what I want you to know though is where does glycolysis occur and you better think the cytoplasm and I want you to know what it's produced in glycolysis I'm going to say two ATP net to pyruvate and two NADH and I told you if you produce ATP in any of the stages you need to know how it was produced and this in this stuff is produced via substrate level phosphorylation and what else do we need to know where does it occur what are the products again if I know what I get out for example I know I produced two ATP then I know that ADP and inorganic phosphate went in if I produce NADH then I know that nad plus went in and I produce pyruvate where did that come from from the glucose so here's the first five stages of glycolysis again do you need to know each of the intermediate glucose 6-phosphate fructose 6-phosphate no I just want you to work know that we start with glucose what do you get what are the products at the end to pyruvate to NADH and to ATP net how is that ATP produced substrate level phosphorylation where do glycolysis take place in the cytoplasm and and they turn to show you right there and that cell on the cytosol the fluid portion of the cytoplasm do I expect you to know all these enzymes I really don't so I'm gonna skip that but you better know that yes are all of these steps regulated yes they are glycolysis is regulated here they show you how but in reality what I want you to know is again where does each step take place what are the products where does it occur and if ATP is produced and tell me let's get this go to the next stage of cellular respiration which is pyruvate processing pyruvate that you produce in glycolysis is converted to acetyl co a and then a CoA will go enter the citric acid cycle alright so that's what they're telling you right here where does pyruvate processing take place in the mitochondrial matrix where does the Krebs cycle the citric acid cycle take place also in the mitochondrial matrix alright so you need to know what are the products with pyruvate processing I know that I'm gonna make two acetyl co a two NADH and two co2 again what does that happen in the mitochondrial matrix so just as a reminder here's the mitochondrion this is the organelle where ATP synthesis occurs notice that it has two membranes and outer and an inner membrane that's gonna be super important because the last stage of cellular respiration takes place in the inner mitochondrial membrane alright that's why it's important and there's the mitochondrial matrix or two stages of cellular respiration take place so yes in pyruvate processing pyruvate goes in we get two acetyl co a we get two NADH and we get two co2 where does this occur in the mitochondrial matrix recall that prokaryotic cells do not have organelles many of them so instead they don't have mitochondria your prokaryotic cells like bacteria instead pyruvate processing takes place in the cytosol the fluid portion of the cytoplasm and notice the word once again oxidize we're stealing energy all right from pyruvate we're oxidizing pyruvate again we're generating two co2 to NADH and two acetyl co e oxidation were stealing energy so pyruvate goes in and pyruvate processing were oxidizing it we're stealing its energy what comes out to acetyl co a that's what's going to enter the next the krebs cycle the citric acid cycle I'm going to produce two nadh and two co2 and so notice that they're telling you you can work backwards if you say acetyl koi was produced then you know that coenzyme a went in if NADH was produced then you know that nad plus was produced and what did the co2 come from well it comes off pyruvate we remove one of the three carbons in pyruvate releasing it as co2 and guess what they're just telling you every single stage it's regulated do I expect you to know this slide no I don't just make sure that you know that every single stage of cellular respiration is regulated so with this we finished with the first half of chapter nine again do you really need to know what gets produced in each step where it happens if ATP's produced how it's produced absolutely all right lots of memorization in this chapter and it all makes sense so it's just a matter of sitting down with it and studying it okay