Citric Acid Cycle 3 - Video Tutorials & Practice Problems
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Citric Acid Cycle 3
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next on deck Alfa Key to glued a rate. Di hydrogen is complex. It's another complex, and it's a lot like Piru di hydrogen is complex. It uses the same co factors. F a deal A poet M T p P. And it also uses Coetzee and any D plus the substrates. A lot of similarities here. Also, this guy has got that nice negative, Delta G. Right again, this is one of the drivers of the citric acid cycle, and we're gonna take Alfa Kita, glitter it and turn it into sucking Ilco a this molecule, right? Yeah. And during the course of this reaction, we are D card box Relating. Right. Um, we are D card box slating this guy coming off. Add co a In you can see Coetzee right there. Sorry. Jump out of the way. You can see co a right there in our product as the weirdest arrow I've ever drawn. There we go. There's koei n 80 plus comes in, gets reduced to N a. D. H. Guess what? That is What's going on with F a. D? Remember what was happening with Piru di hydrogen iss? Yeah, again, biology conserves things. You see a lot of stuff. A lot of similar processes and whatnot recycled all times. Just another example. Another in a long Siri's, I might add. So Step five soeken Ilco a Synthe tastes, um it's got a delta G close thio close to zero. And so this is gonna be one of those kind of readily reversible reactions. The thigh. Oh, Esther Bond is broken, right? And that is going thio supply the energy to make that GTP right to do the substrate level Phosphor relation. Thio combined GDP and inorganic phosphate to form GTP. Um, you know this is that PFI Oh, Esther Bond breaking is gonna give roughly the amount of energy needed for this or sorry, roughly the amount of energy equal to the energy stored in this bond. So it z not a you know, we're not dealing with, like, major energy differences here between input and output. Anyways, um, again, this GTP right, this GTP can be used to form a TPM not showing it here. Showed it in the main citric acid cycle figure. Uh, but, you know, it doesn't really matter for biochemistry because they're, you know, equivalent in terms of their energy value, but we can make ATP from it. And if we did that, we'd be using this nucleus side Die Phosphate Highness. Uh, and you know, that's got, like, a delta G of about zero. So again, it's just a quick conversion. Doesn't cost energy for the cell. Um, difference, really, is that, you know, a TPM GTP are used for different things. GTP, very importantly, is used for protein synthesis. And hopefully you guys remember from intro bio mitochondria have their own DNA. Right? Uh, getting thio back. Thio Endo, Cindy Endo. Symbiotic theory. You know, uh, mitochondria are thought to want to be autonomous cells that lived outside of what air now eukaryotic cells and that they fused with these larger cells to form eukaryotic cells. But they still retain their own DNA, and they still carry out their own protein synthesis, which is why they need some GTP. So not all the genes that mitochondria require actually stored in the nucleus of the cell. They carry some of their own. Pretty pretty cool. I have to say Sooke and eight d hydrogenation. Step six. This is where we make our f a d h to the one and only again. Delta G about zero. We go from sucking eight to again, blocking this molecule to fume a rate right here. Um, this reaction basically converts. Uh, and a nine. Right. This ain't right here to this. I mean, we see right here. And what's important to note is that this is the transform. So this drawing this a little weird, but because we're showing like, a Fisher structure, But hopefully you can see that this is a trans bond. So if I were to redraw it, we'd have our CEO here and c E 00 They're put my minus signs in. So this is a trans bond, not a cyst bond. That's that's the important thing to note. Um, Also kind of interesting thing to take note of is the inhibitor of this enzyme Malin eight Mallonee. This is his mallow, Nate. Not may late. So different molecules, right? May late is going to be one of the substrates of the citric acid cycle. Malin eight is not Malin. Eight is a competitive inhibitor of this enzyme. You can see Malin eight right there and might notice that its structure is very, very close to suck in eight, right? These two molecules here and here they look very similar. The difference is really just the presence of one ch to get rid of that you have Malin eight. So Mallonee acts as a competitive inhibitor. Uh huh. Or second eight. So last thing I want to mention about this is getting back to what I, you know, went on and on about how sucking it this symmetrical. So it's orientation into the active site of sucking D hydrogen. Ace will be random. And just remember, you know, the part of the reason I'm harping on this is, uh, citrate. Also a symmetrical molecule, right? But no, it is pro Cairo. So sickening, not pro. Cairo. So Kenny is symmetrical, but it's not pro Cairo, and its orientation will be randomized into second eight d hydrogen ease. And so if we have labeled carbons, if we have labeled carb labeled carbons, they can wind up here or they could wind up here. And if we have labeled carbons Onley half will come out every round of the citric acid cycle. So we'll get half out the first round, then a quarter and then in eighth on DSO on and so forth. Keep doing more rounds without putting any more labeled carbon in. All right With that, let's actually turn the page and finish up the citric acid cycle.