Pyruvate has three different fates. What are the three differe...

Question

Pyruvate has three different fates. What are the three different molecules pyruvate is converted into? What conditions exist for the formation of each product?

Accepted Answer

Hello and welcome everyone. Here's our next question, which of the following statements about the different fates of pyruvate and their respective products is or are correct. And here's our four statements. Number one, under aroa conditions, pyruvate is converted into acetyl coa which then enters the citric acid cycle in the mitochondria. Number two, pyruvate is converted into glucose in the mitochondria under all conditions. Number three, pyruvate is always converted into ethanol and yeast cells regardless of the oxygen availability. And number four, under aerobic conditions, pyruvate is converted directly into lactate in the mitochondria. And our options for the correct statements are a one only B, one and two C one and three or D one and four. So note that we know one is correct, just looking at this because one is a part of all of our answers. We just need to figure out if any of the other answers are correct. And our only possibility for more than one correct answer is one and something else. So as soon as we find our second correct answer, we're done with this problem. If we're on a test, I'll go through all of them because this is a practice problem. But just, you know, in terms of test taking strategy. So number one, we know is correct under aerobic conditions, py RB is converted into ECL coa which then enters a citric acid cycle in the mitochondria. So normal aerobic cellular respiration. So let's look at number two, pyruvate is converted into glucose in the mitochondria under all conditions. Well, what the citric acid cycle is, what's paired with the mitochondria. The mitochondria is where our aerobic respiration takes place. So we can definitely cross out mitochondria since the pyruvate is not going through the citric acid cycle. So again, in interest of speed, we've already ruled out. Number two. So cross out number choice B but again, let's be a little more thorough pubic can be converted into glucose. This is the process of gluconeogenesis. So if the body's glucose supplies are low, normally we go glucose to pyruvate and glycolysis. But that process can be reversed if we need more glucose. But this doesn't happen in the mitochondria. It happens in the liver and it is not under all conditions by any means. So let's go ahead and cross out number two. Now let's look at number three, pyruvate is always converted into ethanol and yeast cells regardless of the oxygen availability. Well, pyruvate is converted into ethanol and yeast cells by fermentation but not always. So, only under and aerobic conditions when oxygen isn't available. So when oxygen is available, yeast go through aerobic cellular respiration and don't make ethanol. So cross out choice three. Now we look at choice four under aerobic conditions. So oxygen present, pyruvate is converted directly into lactate in the mitochondria. Well, aerobic and mitochondria go together, but pyruvate is not converted into lactate under aerobic conditions. Under aerobic conditions. Pyruvate is converted into glucose in the cru cycle or the citric acid cycle. Pyruvate is converted into lactate under anaerobic conditions. So choice four is incorrect and therefore C and D are incorrect and a one only must be our answer. So in this case, we weren't able to rule out anything early since we had to go all the way through. Number four. But again, our statement that's correct about the fate of pyruvate and its respective product. Just statement. Number one, that under aerobic conditions, pyruvate is converted into acetyl coa which then enters a citric acid cycle in the mitochondria. Hope to see you in the next video.

Pyruvate has three different fates. What are the three different molecules pyruvate is converted into? What conditions exist for the formation of each product?

Key Concepts

Pyruvate Decarboxylation

Lactic Acid Fermentation

Alcoholic Fermentation

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