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Learn the toughest concepts covered in Biochemistry with step-by-step video tutorials and practice problems by world-class tutors

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

Gluconeogenesis 1


Practice - Gluconeogenesis

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glue Konia Genesis is often thought of as simply the reverse of like Hollis ISS, and this is mostly true. As you probably realize, many of the reactions are readily reversible. So many of the same enzymes used in like Allah assists are actually used in glue. Konia Genesis They're simply doing the reverse reaction that they do in like Allah Assists. But this is fine because those reactions have a Delta G that's at cellular conditions very close to zero, meaning that again they're readily reversible. However, remember, there are those three reactions from Glen Collis ISS Reactions 13 and that cannot be reversed because they're too favorable there, too. They have too negative a Delta G, and so new enzymes are going to be required to undo the actions of those particular reactions. And we'll get to that on the next page. For now, let's take more of, ah, top down Look at Laconia Genesis. So, just like like Hollis, ISS has many different molecules that can enter the pathway at different points. Glue. Cuneo Genesis has a variety of feeder molecules that it can use to make glucose, uh, in terms of fats on league lis auroral can enter glue. Konia, Genesis Onley, glycerol. No fatty acids, sterile anything like that for amino acids. Onley, licensing and losing are unable, unable to be glue konia genic. Those cannot be used for glue. Konia Genesis. However, all of the other amino acids are able to be used for glue. Coney of Genesis. It's worth noting, though, that some of these are Onley able to contribute specific carbons. For example, the ketogenic amino acids are on Lee able to contribute certain carbons. Thio, Laconia, Genesis and others are going thio Wind up as ketone bodies. Um, lastly, lactate. The molecule we were just talking about in the context of fermentation can be converted back into Piru bit and used as again starting material for glucose neo Genesis. And here you sort of have the overview of Laconia Genesis, and you can see that many of the same enzymes air being used. However, there are a few four to be exact new enzymes that we're going to talk about on the next page. But for now, let's just talk about the overview of what is required for glue Konia Genesis. And it's basically it's very similar to like Hollis ISS, but opposite of course. So for, like, Hollis iss, you start off with one glucose molecule and from that, well, sorry one glucose molecule and two ATP right to burn to ATP in the preparatory or energy investment phase. And then from that you yield four ATP. That's gonna be a net of to to any D h and to hi ruv eight. And I should for completion sake, say that you need to n a d plus to carry out Blake Hollis ISS. Because, of course, as we saw any D plus is a very important ingredient to Glen Collis iss. As, um, you know, there's this whole fermentation process solely dedicated to regenerating n a D plus from n a. D h. So this is like Hollis is right here and you can see that glue Konia Genesis is almost the opposite, right? We need to take to make one molecule of glucose we need to take to piru of it four ATP to GTP and thio n a d h. So you can see here that actually were using mawr energy to build a glucose than we um Then we get from actually ca tabal izing a glucose. So, uh, luego neo Genesis is Mawr energy intensive than like Hollis. ISS provides energy, but But this is okay. This is okay. And, um, you know, for one thing, when we get to cellular respiration, you'll see that even though you might not be yielding all your ATP back from, like, elliptic part, once you get over to oxidative phosphor relation, you're a teepee. Yield is just bonkers. So, uh, this slightly extra amount of energy that ourselves need to use to generate blue konia Genesis Well, they'll get a return on that investment from cellular respiration. However, glue konia Genesis is also sometimes used just thio provide glucose for cells to continue, like Hollis ISS in periods of intense energy demand. Glen Collis ISS and glue Konia Genesis also both occur in the site is all which should make sense. That's where all the enzymes for Glen Collis ists are. So of course, glue. Konia Genesis is also going to occur there, and really important part to think about is that the two pathways are very tightly regulated, and this is because we don't want a futile cycle. So let's let's think about this for a second. If we have looking at this figure, if we have, like Hollis, ISS and Glue Konia Genesis running simultaneously, What's happening? Are we really generating anything? Every action taken by the glycol Igic enzymes will be undone by the glue konia genic enzymes. So it's almost like we're, you know, spinning our wheels, right. We're running in place. We're expending energy, but we're not really getting anywhere for that. That's what we call a feudal, a futile cycle. And the ourselves just can't afford thio waste energy like that. So these two processes are regulated. Uh, they're they're very tightly regulated, and they're regulated in such a way that when one pathway is running, the other is shut off. And this is also important from enzymatic standpoint. If you think about the fact that many of these enzymes air being shared well, these enzymes, it's very easy for them to reverse their reactions. So they they need some sort of oversight, telling them sort of which way they should be pushing those reactions. And again, you know, for like Allah assists, we have those three particular reactions that drive the whole pathway. So you know the regulation of those particular enzymes is going to play a big role in actually controlling, like Hollis Iss and glue. Konia Genesis. And you'll see that when those Glick elliptic those specifically like politic enzymes are active, the specifically glue konia genic enzymes will be inactive and vice versa. When the specifically glue konia genic enzymes are active. Those, uh, enzymes specific to black Allah assists will become inactivated. And, of course, again, those of the enzymes from reactions one, three and 10. All right, let's flip the page and actually talk about those reactions specific to glue Konia Genesis.