Question

Give a basic description of four main stages of cellular respiration.

Answer 1

Answer. The four steps of aerobic respiration are-

1. Glycolysis- It takes place in the cytoplasm of the cell. It's substrate is a molecule of glucose that divides to form 2 molecules of pyruvate.
2. Oxidative decarboxylation- It starts with pyruvate and forms acetyl CoA through this process. Because two pyruvate are produced through glycolysis, thus this process ends up in forming two molecules of acetyl CoA.
3. Kreb or tri carboxylic acid cycle- It starts with acetyl CoA and ends up forming carbon dioxide and water molecule. Two molecules produced by oxidative decarboxylation undergoes this kreb cycle. It occurs in mitochondria.
4. Oxidative phosphorylation through electron transport system- It occurs in inner mitochondrial membrane. It produced ATP from the coenzymes produced in the above three processes. It produced 8 ATP from glycolysis, 6 ATP from oxidative decarboxylation, 24 ATP from two kreb cycles.

So, overall 38 ATP are produced, out of which two are lost in the membrane transport.

To summarize, a molecule of glucose through aerobic respiration produces 36 ATP.