Which reactions of the citric acid cycle transfer energy as NADH?

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Hi everybody. Our next question says which reaction or reactions within the Krebs cycle results in the formation of reduced nicotinamide, adenine dinucleotide or N A DH. So let's recall that there are three reactions within the creb cycle that use N AD plus as an electron carrier. So I'm just going to post a really rough overview of the creb cycle. So this doesn't have all the names filled in. So we'll have to remember that. But just to give us sort of the overview here and we can see the three steps where we have N A DH produced so up and we'll go out and number the steps. So we can be able to refer to them. So we have step 123, four, 567 oops seven and eight. And we can see that N A DH is produced in step three and step four and, and step eight. So let's think about what is going on in these steps. So in step three, we've had citrate in step two, they got converted to isocitrate. So we have isocitrate as our reactant isocitrate and notice that we're also going down by one carbon carbon dioxide is being produced. So we're going to go down from isocitrate to alpha ketoglutarate. And then in the very next step, we have another oxidation of our reactant alpha ketoglutarate and reduction of N AD plus that's like a version of alpha ketoglutarate. Notice again, we're going down by carbon, we're losing a carbon dioxide to Suan Co A. So we actually need to add one more thing in here. I've shown, you know, the reduction of N A plus the production of CO2. And we need to show that we have coenzyme A coming in to be attached to our molecule here. So we have two reactions in a row. And then finally over way over on step eight, we know that the product is oxy acetate. We've come back around and regenerated our initial molecule there and the reactant is malate. So the last reaction that produces N A DH is this conversion of malate to oxalacetate. All the enzymes that catalyze these steps are dehydrogenase. So we have isocitrate dehydrogenase, alpha ketoglutarate, dehydrogenase and malate dehydrogenase that catalyze these three steps. But again, our reactions within the crep cycle that result in the formation of reduced N A DH are the conversion of isocitrate to alpha ketoglutarate. The conversion of alpha ketoglutarate to succinyl coa and the conversion of malate to oxalacetate. See you in the next video

Which reactions of the citric acid cycle transfer energy as NADH?

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Key Concepts

Citric Acid Cycle

NADH Production

Energy Transfer in Metabolism