Question

in detail how is energy stored in pyruvate converted into adenosine triphosphate (ATP) in eukaryotic cells?

please explain with lots of detail as I am struggling to understand this concept. :(

thanks in advance.

Answer 1

Cellular respiration is the process of breakdown of glucose into carbon dioxide and water to generate ATP. ATP is the energy currency of the cell and is used to perform all the metabolic activities.

The first step, glucose is broken down into pyruvic acid and the process is called as glycolysis. The electrons present in glucose are passed onto pyruvic acid. It takes place in cytoplasm of all the prokaryotes and eukaryotes. High energy electron carrier NADH is produced in this process.

In the second step, pyruvic acid is broken down into acetyl coenzyme A and carbon dioxide. This step takes place in mitochondrial matrix with the help of enzyme pyruvate dehydrogenase. NADH is also produced.

In the third step, acetyl coenzyme A enters citric acid cycle taking place in mitochondrial matrix. Acetyl conezyme A is broken down into carbon dioxide and water. NADH and FADH2 is also produced.

All the high energy electron carriers which are generated in glycolysis, pyruvate oxidation and citric acid cycle enter electron transport chain taken place in inner mitochondrial membrane. They donate their electrons to the first complex which are than passed on to the next complex and ultimately accepted by oxygen to form water. Water is the byproduct of cellular respiration.

When electrons are transported from one carrier to the other, protons are also pumped from mitochondrial matrix to intermembrane space. This results in differential concentration of protons across in the mitochondrial membrane leading to the formation of proton gradient. These protons are diffused back into the matrix by ATP synthase enzyme. The electrochemical energy stored in proton gradient is used by ATP synthase enzyme for the synthesis of ATP.

So the electrons present in glucose are transferred to NADH and FADH2 which than enters electron transport chain to generate proton gradient which is further used for the synthesis of ATP.

You can see all the steps in detail below -

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