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Review 2: Biosignaling, Glycolysis, Gluconeogenesis, & PP-Pathway


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Step nine is carried out by analysts. And again, this has a delta G close to zero, meaning we've got our forward and reverse arrows present. And additionally, um, let's put in our carbon numbers, because again, this is important. Your professor likes to test it, so we have three or four, two or five and one or six. And this reaction is going to take to phosphate blistery and turn it into phosphate, anal, piru bait or pep. And I just love calling it pet. And actually, in the process, we will be releasing in H 20 So we're oxidizing this molecule right now. And, um, let's put in our carbon numbers on the product here. So too five and one or six. And let's go ahead and take a look at Step 10 and step 10 carried out by Peruvian kindness. This is another enzyme really important, one that you should know. Um and you can see that this has a very negative Delta G, meaning it's a super favorable reaction. We're gonna talk more about that later, and it takes pep and a d. P n converts pep into Peruvian and generates an ATP through substrate level foster relation. And actually, Pirou of it comes out of this reaction in its in all form and is quickly converted by itself. It converts to the Keto form. So here we're showing we're showing that Keto form. But, you know, it actually does immediately come out in the in all form anyhow, just to be super thorough. Let's number are carbons again. 34 to and then finally here to five and one six. All right, so uhh the You may have noticed that the like a lot of the black allergic reactions are readily reversible. However, there were three that are super negative at physiological conditions because remember that reaction. Seven, uh, it had of super negative Delta G, but in cellular conditions, it's actually much closer to zero. That's why it has the foreign reverse arrows. Uh, but reactions 13 and 10 are not readily reversible. Those air reactions one and three year like what I call the commitment steps and 10. This last step that converts, um pepped into Peruvian kindness is also has a very negative delta G. And these three reactions basically drive like Hollis is forward because the others are all readily reversible. But these reactions are ensuring the whole pathway moves forward in that one direction. And that's because again they have a negative Delta G and are very favorable reactions. Now it's important to note that other molecules actually can feed into like Allah assists. But it's always going to cost to a T. P. So there's no cheating the system, really. You know, you're gonna have to pay the piper no matter what you do. But you don't necessarily have to start with glucose, which is a good thing because your body is not always going to have glucose available to it. So obviously, if you do start with glucose, you turn it into glucose six phosphate. And that's what feeds into Glen. Collis is right. That is the substrate for Step two of Glen Collis ISS. If you have lactose, lactose is a dye sack right and it gets broken up into glucose and galactus. Well, we know what's gonna happen to glucose, right? Glucose is going to get converted to glucose six phosphate and enter Glen Collis is that way. Galactus, on the other hand, actually has to get converted. Um it has to go through. You know, a couple reactions before it's actually ready to enter the glow clinic pathway, monos or manos gets converted. Thio Mannus six phosphate which gets converted into fructose six phosphate. And that's what enters Theglobe politic, pathway and fructose gets converted into fructose one phosphate. And then that is actually broken into glycerol hide and D H A p, both of which will get converted into G three piece so we can see this. Here is fructose this molecule right here. I'll even write it in fructose. Here we have fructose one phosphate. This is fructose one boss feet and let me just jump out of the image here. Right next to that we have a D h a P and G three p. So here's our D h A P. This is RG three p and the molecule Glessner Alga hide. Well, that's basically just G three p without that phosphate group, Right? Uh G three p is glycerol to hide three phosphate. So basically, what's gonna happen is you're just gonna add a phosphate under glycerol to hide, and then you have cholesterol died three phosphate and D h A p. Well, we already looked at how you turn that into G three piece. So the main point is fructose is going to enter as G three p. Now glycerol can also enter like Hollis ISS. But on this is gonna become more apparent in a moment when we talk about fermentation. Glycerol is not the best choice for entering like Allah assists, and the reason for that is glycerol gets converted into glycerol three phosphate, which gets converted into, uh, G three p, which gets converted into glycerol to hide three phosphate. And this process uses one ATP and generates two ATP. Now, remember were saying before it always cost to ATP. Well, it costs two ATP per six carbons. Uh, this glycerol is only contributing three carbons, so it only cost 1 80 p. That's where that discrepancy comes in on degenerates to a T. P. So that's normal, right? Uh, you pay 1 80 p per three carbons. You get to a teepee back for three carbons. So for talking about six carbons, that would be paying to 80 p and generating 4 80 p for the six carbons. Um, the problem is that normally for six, carbon molecule like glucose, right? We generate two and a th right. So the problem with glycerol is that for three carbons we generate to any D. H. So we're generating twice as much any D. H as we want to be. And we'll see why. Momentarily why This is a problem. Why generating this excess and a D h, um means that, like Hollis, ISS won't be sustained with fermentation. So the end game of all of this is that glycerol is really only used in aerobic conditions because it's going to generate Maurin a D. H. Than three other fear molecules. And because of that, um, we can't rely on fermentation to keep like Allah assists going. And this is going to again become apparent when we turn our attention to Glen Collis ISS. The last thing I want to point out is glycogen fuss for Lee. So before when we were talking about bio signaling, we talked about how the cell will store. It's glucose as glycogen. Well, when glycogen gets broken down, it actually doesn't get broken down back into glucose. It gets broken down into glucose one phosphate, so glycogen phosphor lace actually breaks down, breaks down glycogen into glucose and phosphor relates it and that glucose one phosphate has to be turned into glucose six phosphate to enter Glen Collis IHS. This is a simple rearrangement, though, so no big deal. But the main point is this is glucose one phosphate coming off and it has thio be converted into glucose six phosphate before it can actually enter. Glen Collis is all right, let's flip the page.