before watching the answered each question. You should attempt those questions on your own. I'll pause briefly between each questions so you can pause the video. But you can also just try all the questions and then watch the video explanation. Now question one. Which of the following is not true of the Piru di hydrogen is complex and the answer is that Biotin participates. Biotin doesn't have anything to do with Piru. Di hydrogen is complex. If you recall the co factors, it uses our TPP let poet and f a d All of the rest of the statements are true way have two different file groups with TPP and with the CO A, um both Kennedy and F d participate, right. We're gonna generate n a d h from n a d plus and we're gonna actually use f A D to do that. And these reactions indeed occur in the mitochondria in the Matrix, to be precise. Great question, too. Excuse me. Glucose labeled in the 3rd and 4th carbons where C 14 is converted with. I'm sorry with C 14 is converted to Piraeus bike like Hollis is and two acetyl coa A with the PIRA video. Hydrogen is complex. Where is the labeled seal koei or were, Um, where is the label? In the acetyl COA? The answer is, there's none there at all. Uh, if you look higher, elevate here is Pirou of eight, and you probably remember this is carbon one or 62 or five and three or four. And when this is converted into a seal CO A. This gets de car box, elated as co two. So all that remains our carbons one or six or two or five from the original glucose. Now Malin eight is a competitive inhibitor of sucking it di hydrogen iss. If if Melanie is added to the mitochondria, we would expect the product of sucking it di hydrogen ISS to decrease in concentration. Right? So few Marie. We would expect that to decrease in concentration. Uh, we would actually expect sucking it. Thio increase in concentration, right? If sucking it di hydrogen Issa's being inhibited, then sucking it will probably build up a little bit, Uh, and the's. Of course. Well, Alfa Kita glued or eight. Nice to sit trade are precursors to suck in eight, and Piru of eight is not even a part of the citric acid cycle it comes in before the citric acid cycle. Now which of the following is not an intermediate of the citric acid cycle? Tricky question, right? It's actually a Segal Co A. And this might surprise you. Acetyl coa is not an intermediate. It's what enters the cycle. But it's not considered an intermediate, whereas both citrate what it enters the cycle to become an axle or acetate. The thing that combines within the cycle our intermediates of the citric acid cycle. And of course, Maley and Isis citrate are also intermediates of the cycle ox alot, acetate uniformly labeled with carbon 14 in all carbons, meaning that all carbons have the same radio activity. That same radio label eyes added to the mitochondria with an adequate supply of acetyl coa A that is unlabeled in the first cycle. How much radio activity will remain in xolo acetate answers 50%. So if you recall Xolo acetate is made of or carbons, right, I'm not gonna try the whole molecule. This is like my mini XLR acetate, and it combines with two carbon Segal CO a right and then you form this molecule citrate. Okay, So you scroll down a little so you can see my drawing. This carbon and this carbon are going to d car box late in that in this turn of the cycle, you know, So thes two are going to disappear Now, we said that all of these groups, all of these Axler acetate Swor labeled right. But these two carbons are gonna de car box late those air, these two carbons right here. So on, Lee, these two carbons are gonna remain in the next turn of the cycle. Thes acetyl coa carbons were unlabeled, right? So these air carbon 14 and these air regular carbon 12 right? So then in our next doc sallow acetate, I mean, straight up here, we're gonna have carbon 14. Excuse me. We are going Thio have to carbon fourteens and can't really say which to It's gonna be way. Just don't know, so right, because there's the random ization of certain its orientation. So we can't say which to It'll be right. It could be the other two. I've just drawn it is to hear, but Well, the point is, we're Onley gonna have 50% of that radio labeled carbon remaining in the next turn because we're gonna lose two D car box elation in that first turn. All right, let's flip the page.
