Review 3: Pyruvate & Fatty Acid Oxidation, Citric Acid Cycle, & Glycogen Metabolism
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in these videos were basically gonna be picking up our story where we left off last time. You might recall that we ended with, like, Hollis iss last time. That's sort of where we ended our story of cellular respiration and you can kind of think of like Allah assists as act one of cellular respiration in these videos were gonna be covering Act to which is the citric acid cycle. And in fact, next time we will finish with the third and final Act, which is going to be electron transport and oxidative phosphor relation. So the point is, if you're not totally comfortable with what was going on and like Hollis iss, you might want to go and review that before jumping into these videos because we're just gonna be continuing this story, and we're not really going to be reviewing that material. You know, The assumption is you already understand it by the time you're here. So let's begin with pirouette oxidation. Now, uh, little recap. You might recall that like Hollis, ISS ends with glucose being turned into two molecules of pyro of it, and that all of this is taking place in the site is all. Now our pyro of it is going to be transported from the side is all into the mitochondrial matrix. And what's what's important that I want you Thio, Make sure you're aware of, uh is that we are only going to be looking at the path of one piru bait, right? Remember that there's two coming off of glucose. So if you are trying Thio, you know, do you sort of like mental accounting of all the substrates and products and all that? Be aware that, you know, if you're coming from glucose, you need to double the numbers that you're seeing now, Um, And when we sort of finish up, our discussion of the citric acid cycle will be going through, you know, Ah, grand accounting of all the substrates and products and all that sort of stuff that we have talked about and all the very explicit about the numbers relating 21 glucose, etcetera. So just for now, be aware we're only looking at the path of one Piru bait, not the two that are going to come off of glucose. Okay, without further ado, Piru vit d hydrogen. It's This is going to pick up pair of it Once it enters the mitochondrial matrix and you can see from its Delta G. This is a favorable reaction and it's actually a complex. This is actually complex of three enzymes, but you don't really need to worry about their names. I've included them for the sake of thoroughness, but don't worry about memorizing it. It's not very important. What you do need to know is the uh what you do need to know are rather these substrates products co factors and how this, um, enzyme is regulated. So let's start with the substrates again. We are doing our reaction with Pirou bit. That one's kind of obvious. You should know the structure of this molecule already be very familiar with it. And we also use the substrate n 80 plus and coenzyme A and just take note. This is the reduced form of coenzyme A. That's what that s H is symbolizing. And, uh, we are going to generate from this reaction. Our products are going to be co two. This is gonna come off a co two. We're gonna talk more about that momentarily. Are any d plus is gonna be reduced. Thio any d h and talk about more. A little more about that in a second to and lastly, our product is going to be acetyl co our main product, right? What Piru of it is going to become and what's going to carry on in the subsequent reactions is acetyl co A. This molecule you see here Uhh! So the co factors, you need to know what they are. But the only note I really wanna make about them is f a D. Because it's the kind of interesting what happens here. You see, uh, f a d is going to be in the course of the reactions f a D actually me right this over here f a d is going to be reduced thio f a d h to now The reason I've drawn my arrow kind of weird and backwards to demonstrate this is because this is actually going thio f a d h two is actually going thio reduce an a d plus and turned back into F a. D. Right. This is a co factors. So it's going to be, you know, we're going thio be reusing this f a d um, in subsequent reactions, so f a D gets reduced to f a d h two that's going to reduce our substrate n e d plus into an eight th We're gonna regenerate f a d and, uh, you know, pick up another pair of it. Do you know the reaction? So on and so forth. So kind of interesting little note there and last. Just wanna again make the point that, like Hollis iss like Hollis iss was taking place. That was weird. Esque like Hollis IHS was taking place in the cytoplasm. I'm sorry. Call it. The site is all. And the reactions are now Piru right has moved into the mitochondrial matrix. So that is where all of these reactions that we're gonna be talking about now taking place Last note. I want to talk about everyone's favorite subject. I know counting carbons. And you might recall little review here that from like, Hollis iss we are left with to Piru bait. And they will have the numbering scheme of one or six thio 45 and three or four, right? Depending on which, you know, part of the glucose molecule the pirate came from a C. Delco A is going to contain carbons one and six or I'm sorry. Carbons one and two or six and five. Because this carbon three or four depending on which part of the molecule is coming from this is going to be what is D card box. Elated. So, uh, this is how our carbon numbering is going to work out through these reactions. And just to be crystal clear, the numbers we're talking about are not the carbon, the carbon numbers that correspond to the numbering of Piru of it. Right? Piru Bates numbering. And I'm gonna write it below Pirou of its carbon numbering is theocracies it. It's one Thio three, right? So technically, we're left with carbon number three and two of Piru of it. But those our carbons number one and two or six and five from glucose It's a lot I know Get super hairy. So So I'm trying to be as a Z explicit as possible about this. So again, our a c Delco A is going to contain either carbons one and two or six and five of the glucose numbering system and those are actually carbon numbers three and two from Piru. Bit okay with that, let's turn the page