Question

When one molecule of pyruvic acid undergoes krebs cycle, how many $C{O}_2$ molecules are formed?

• A. $6C{O}_2$
• B. $3C{O}_2$
• C. No $C{O}_2$ formed
• D. $2C{O}_2$

Answer 1

The correct option is B $3C{O}_2$

Three $C{O}_2$ molecules are formed. One $C{O}_2$ is formed during oxidative decarboxylation of pyruvic acid. Two $C{O}_2$ molecules are formed in krebs cycle, one during the conversion of 6-carbon oxalosuccinate to 5-carbon $\alpha$-ketoglutarate and the other during the conversion of $\alpha$-ketoglutarate to 4-carbon succinyl CoA.