Look ahead to Figure 21.8 for the citric acid cycle.
a. Draw the structures of the reactants in steps 3, 6, and 8, and indicate which hydrogen atoms are removed in these reactions.

Question

Look ahead to Figure 21.8 for the citric acid cycle.

a. Draw the structures of the reactants in steps 3, 6, and 8, and indicate which hydrogen atoms are removed in these reactions.

Accepted Answer

All right, hello everyone. So this question is asking us to draw the structure of the product and indicate the water's atoms added to the reaction in step seven of the citric acid cycle. So for this question, recall first and foremost that the citric acid cycle, otherwise known as the TC A cycle or the crept cycle is the third stage in catabolism for aerobic organisms. So the citric acid cycle begins with a molecule known as Aceto coa. So when acetylate is brought into the citric acid cycle along the way, it generates a TP and numerous other co enzymes throughout the course of the pathway and also co two. So with this in mind, let's just go ahead and list out the steps of the TCA cycle. Now, as mentioned before, right, there are going to be products like A P and carbon dioxide in the citric acid cycle. But for this question, I just want to focus on the main organic starting materials, intermediates and intermediates. So anyways, with that being said, I'm going to specifically list out the products of each step starting off with the first step, we have the conversion of a PSEO coa into a compound known as citrate from there, citrate is converted into isocitrate in the second step. And in the in the third step, isocitrate is converted into alpha ketoglutarate. In the fourth step, alpha ketoglutarate is converted into Sueno Koe. In the fifth step, we have Sueno Koe going to succinate in step number six, we have succinate being converted into fumarate. Step seven is fumarate being converted into mate or mate as you may have heard it before. And then the last step of the citric acid cycle is the conversion of malate into ox solo acetate. And then the cycle repeats again right from step one to step eight. And so with this in mind, let's go ahead and focus our attention on step seven in particular. Now, step seven, according to our overview, here is the formation of mate. And so the starting material is the product of the prior step which is fumarate. So fate is going to be our starting material. So that's what I'm drawing right now, fumarate is a dic carboxylic acid or a decarboxylate here. And notably, there's a double bond, there's an alkene in the structure of fate. So fate is reacting with water to produce malate. And this reaction is catalyzed by an enzyme known as pumera, which makes sense because it's acting on fumarate. Now, what pumera is going to do is it's going to add water across both carbons of the alkane present in fume. So one carbon gains a hydroxy group and the other gains a hydrant. So starting off on carbon number one, here, we have our carb box elite group. And so carbons two and three are each going to have a component from water. And then carbon number four is that other carboxylate group. So one carbon, namely carbon two is going to gain here our hydroxy group which I'm labeling in red because it comes from water and carbon number three gains hydrogen. And that completes our structure of Malade and there you have it. There is our final answer. And so with that being said, thank you so very much for watching and I hope you found this helpful.

Look ahead to Figure 21.8 for the citric acid cycle.
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a. Draw the structures of the reactants in steps 3, 6, and 8, and indicate which hydrogen atoms are removed in these reactions.

Verified video answer for a similar problem:

Key Concepts

Citric Acid Cycle

Reactants and Products

Hydrogen Atom Removal