Question

The site of TCA cycle in respiration and ATP synthesis is

• A. Mitochondrial stroma.
• B. Mitochondrial matrix and oxysome.
• C. Cytoplasm.
• D. None of the above.

Answer 1

The correct option is B Mitochondrial matrix and oxysome.

Glucose is broken down into pyruvic acid in the process of glycolysis, which occurs in the cytoplasm. During the process of aerobic respiration, the pyruvic acid is transported to mitochondria, where it is decarboxylated into acetyl-CoA. Each molecule of acetyl-CoA is metabolised by Krebs cycle, which occurs in the mitochondrial matrix. The process of Krebs cycle generates reduced coenzymes, which are oxidised by mitochondrial electron transport chain. During oxidation of reduced coenzymes, ATP is synthesized by the process of chemiosmosis, carried out by oxysomes present on the inner mitochondrial membrane. This process of ATP synthesis is called as oxidative phosphorylation.