Question

When one molecule of glucose is completely oxidised during aerobic respiration, how many molecules of carbon dioxide are released due to tricarboxylic acid cycle?

• A. One
• B. Two
• C. Three
• D. Four

Answer 1

The correct option is D Four

Six carbon dioxide molecules are released by complete oxidation of one glucose molecules. Two carbon dioxide molecules are released during oxidative decarboxylation reaction when the glycolytic products, that is two molecules of pyruvate are converted into two molecules of acetyl CoA and channelled into the Kreb's cycle. And four carbondioxide molecules are released during the Kreb’s cycle, during the breakdown of two molecules of isocitrate to alpha-ketoglutarate and the breakdown of alpha-ketoglutarates to succinyl CoA.