 At the risk of terrifying you, please don't be terrified. I've taken all the stages of cellular respiration, found very complex but accurate depictions of all the chemical reactions that are taking place in these processes, and I've put them all together onto one diagram. I promise you, I mean I really, really promise you that all of these details are not things. I'm going to tell you the pieces that we are going to remember, but I don't want you to forget that this is a phenomenal example of a cellular mechanism that ultimately is designed, is set up to get the energy from a glucose molecule and transfer that energy into ATP molecules. We know that ATP is the molecule that is easy for us to use. We know that there is potential energy, chemical energy stored in the glucose molecule. It's actually a lot of it. So your body, your cells go through this fantastic process of taking that glucose molecule and look, if you look really close at this, maybe I'll zoom in a little bit for you. If you look close, you see that we actually have the glucose molecule here to start with. This first, we're taking that, we're sending it through a doodoo load of chemical reactions and the chemical reactions are heading this direction and then back up this direction. This guy's important and I'll tell you who that is. That guy enters this process and then we've got this cycle that goes around and around in circles. That's a lot of chemical reactions. In fact, I think there's like almost 20 enzymes that are involved in this series of chemical reactions. We're not going to keep track of all of those chemical reactions. The products made during these series of chemical reactions, many of the products are called high energy electron carriers. And we'll totally, in this section, I'm going to tell you about these guys and they go to the electron transport chain and that's where we get the ATP. So we're going to look at, we start with glucose. We go through a process called glycolysis. Gly, yikes, colysis. That's this part up here. Glycolysis taking glucose and turning it into pyruvate. We then modify pyruvate. We turn pyruvate into acetyl-CoA. Acetyl-CoA enters the citric acid cycle and that whole thing produces high energy electron carriers that go to the electron transport chain. That's it. I'm going to draw it out for you and we're going to keep track. We're going to like put that big picture that I just said. We're going to put it on another sheet just so we can see it a little more cleanly and we don't get distracted by all that chemistry. But if you're like, dude, what? I want to know what these molecules are. There's 20 chemical reactions. That means there's 20 enzymes that are facilitating these chemical reactions. Knock yourselves out. You can go as deep into this as you want and see all the cool stuff that's happening for us. We're going to boil our big picture down to four stages and just a few molecules. So we're going to start out with glucose and of course. And glucose is going to go through a process called glycolysis. We named that already. Yes. These are the stages that I'm putting on the left side of this. You saw it. The outcome of glycolysis is a molecule called pyruvate. Pyruvate, interestingly, maybe I will not say any words about that. Maybe I'll save that for when we talk specifically about glycolysis. Pyruvate goes through a brief, a very brief modification and gets turned into acetyl-CoA. And I'm just going to go ahead and name that the modification of pyruvate. And it's like one one reaction. But it does take that pyruvate and change it into acetyl-CoA. And then the acetyl-CoA is the molecule that directly enters this cycle called the citric acid cycle. And it looks, I kind of feel like the cycle goes this direction. And acetyl-CoA enters it. I don't like how I drew that because I feel like, but we'll look at this one in more detail as well. Okay, so this is the citric acid cycle. Cycle, what? Cycle? And then all of this produces these molecules that I'm going to talk about in one second. Because I'm not okay, hold on. We got to do it, we got to do it like a, like a this. We're going to say one of the outcomes of this, I already mentioned them, they're the high energy electron carriers. And all of these processes produce these high energy electron carriers. So let's just make a little note of these guys. High energy electron car. We'll throw some tires on those things. And those are what are going to the electron transport chain. The electron transport chain is where we end up with MAD ATP. Let's look, I think we should look at the high energy electron carrier just for perspective here. But that's something we want to keep track of. We want to know where, in this whole process, we want to know where we're going to get these high energy electron carriers. They are a molecule to track. So things we're going to keep track of. High energy electron carrier. What else might we want to keep track of? How about ATP, home kids? This, I'm assuming somewhere in this, we're going to get ATP, right? That's like the whole point. I'm telling you a little hint that those high energy electron carriers play a big role in producing ATP in the electron transport chain. Other folks we might want to keep track of. Let's keep track of the waste products. If we go back to the chemical reaction for cellular respiration, we know we're breaking down a molecule of glucose. And that glucose molecule has six carbon atoms. Where do they go? They actually, every single one of them gets turned into carbon dioxide. And what do you do with carbon dioxide? That was not vomiting it up. You don't vomit carb. Well, hopefully you don't. I don't even want to think about that. Instead, you breathe it out. Carbon dioxide is a waste product that you breathe out. Oxygen, one of the things that is required in cellular respiration. And you at the end of this lecture will know exactly why you need oxygen to survive. Carbon dioxide is one of the byproducts of this process. And we breathe it off. So for every molecule of glucose, we're going to breathe off six molecules of carbon dioxide. The other thing that is not as relevant, like we're not going to see water and where it comes from until the very end. The rest of these guys will actually see them through the whole process. But the water we'll see at the very end. But let's keep track of that as well. Okay, I do want to say just a couple more things about the high energy electron carrier. Because this is literally how I think of it. There are multiple kinds of electron carriers. In my head, I call them electron cars. And they go back and forth to being an empty electron car or being a full electron car. A full electron car has two electrons attached to it. And I just would love you to accept that these are high energy electrons. They have names. The electron carriers have names. NADH2 and FADH whatever. Hmm. Nope. We're putting them all in one group because their job is to carry these high energy electrons to the electron transport chain. This sounds weird, but don't worry. We're going to keep after like why that matters. And the high energy electrons, high energy. We took energy from the glucose molecule and captured it in high energy electrons and ended up with a car carrying two of them. Are you comfortable with that? If the car gives up the electrons, lets the passengers out of the car. Then it goes back to being an empty car and it's ready to carry two more high energy electrons which likely will be generated from the process of cellular respiration. Either glycolysis, the processing of pyruvate, or the citric acid cycle. Okay. Shall we see? I think. Am I happy? This is our box that we're going to put everything. We're going to layer in all the things to keep track of in each one of these stages. Let's start with glycolysis.