Where in the mitochondria is ATP synthesized?

Question

Accepted Answer

All right. Hello everyone. So this question is a true or false. Correct the statement. If it is false, the mitochondrial matrix is where most ATP is synthesized. So first and foremost, just to clarify, right, recall that A TP stands for adenosine triphosphate and is our primary energy currency. So A TP is synthesized primarily through three different pathways. These pathways include glycolysis, followed by the TC A cycle, otherwise known as the citric acid cycle or Krebs cycle. And then we have oxidative phosphorylation or Oxo as I'm writing here for short. Now, these pathways, these reactions I should say make up collectively the process known as cellular respiration or aerobic respiration. Now, of these three pathways, our focus is on where the most A TP is synthesized. And that if you recall, in other words, the pathway where most A TP is produced is after oxidated phosphorylation. This is because after oxidated phosphorylation, approximately 28 molecules of A TP are produced per one molecule of glucose. The other two pathways produce about two molecules of A TP per molecule of glucose. So, the difference is drastic. All right. So first and foremost, why does oxidative phosphorylation produce this much at P. Well, let's talk about it. First recall that the mitochondria has two distinct membranes. We have an outer membrane and the inner memory. So because we have two membranes, there is a space in between them. So let's keep that in mind. The first component of oxidative phosphorylation is the electron transport chain. So within the inner mitochondrial membrane, we have a series of protein complexes, these complexes make up the electron transport chain. Now, before I continue on with this thought, let me actually go ahead and make this drawing a little bit bigger just for visibility sake. So I'm just adding a little bit more space here in between the two membranes of the mitochondria. But in any case, right, we have these protein complexes inside of the inter mitochondrial membrane. So the electron transport chain is characterized as a series of redox reactions involving these protein complexes as a result of these redox reactions. What happens is that protons are being transferred from the mitochondrial matrix into the space between the two membranes of the mitochondria. So that's the inter membrane space. And so because this inter membrane space is all of a sudden being filled with protons, these protons are going to want to escape, right? Because now a gradient has been established, the inter membrane space has a high concentration of protons. And so they're going to want to move towards the mitochondrial matrix where there's a relatively low concentration of protons. So how did they achieve this movement? Because the protons themselves are a charged species. So they can't pass through the membrane themselves. This is where ATP synthese comes in. Now, ATP synthese is an enzyme also embedded within the mitochondrial membrane, the inner mitochondrial membrane to be precise. So what happens here is that these protons because they want to move from an area of high concentration to an area of low concentration, they do so through ATP synthese. So as these protons are being shuttled essentially from the inter membrane space into the mitochondrial matrix, this also catalyzes the formation of ATP, this movement of protons provides enough energy to convert ad P adenosine diphosphate into A TP. So once you have the protons movie, once you have the protons moving inside of the matrix, what happens is that a newly formed molecule of ATP is also released into the mitochondrial matrix. And because you have a high concentration of protons in that intramembrane space, many molecules of ATP are produced as a result of their movement to the mitochondrial matrix. So a lot has been said up to this point. But here let's go back to our objective is the statement given true. The statement given says that it is the mitochondrial matrix where most of the ATP is produced. Well, recall that the ATP that's produced from oxidative phosphorylation is created by ATP synthese. And where is a TP synthese? Well, a TP synthese is embedded within the inner mitochondrial membrane, not the mitochondrial matrix. So technically right, it is the inner mitochondrial ma matrix, excuse me, inner mitochondrial membrane, the membrane where most of the ATP is produced instead. So the statement here is false and now I can scroll down a little bit to reveal the final answer. So the final answer reads as follows. The statement is false because the inner mitochondrial membrane is where most ATP is synthesized and there you have it. So with that being said, thank you so very much for watching and I hope you found this helpful.

Where in the mitochondria is ATP synthesized?

Verified video answer for a similar problem:

Key Concepts

Mitochondrial Structure

ATP Synthesis

Chemiosmosis