Answer to Question #222493 in General Chemistry for Asefa

Question

1. Although oxygen does not participate directly in the citric acid cycle, the cycle operates only when O2 is present. Why?

2. List the five coenzymes involved in decarboxylation of pyruvate by PDC.

3. How does the citrate synthase prevent the wasteful hydrolysis of acetyl CoA to acetate and CoA?

4. What is the ratio of the total number of the lipoyl groups of the E2 core in E. coli PDC to that of mammals?

5. British anti-lewisite (BAL), which was designed to counter the effects of the arsenical war gas lewisite, is useful in treating arsenic poisoning. Explain

Answer 1

1. As a result 9 ATP are generated by electron transport-oxidative phosphorylation per turn of the cycle. Molecular oxygen does not participate in the citric acid cycle. However, the cycle operates only under aerobic conditions because NAD+ and FAD cannot be regenerated in the absence of oxygen.

2). Five coenzymes are used in the pyruvate dehydrogenase complex reactions: thiamine pyrophosphate or TPP, flavin adenine dinucleotide or FAD, coenzyme A or CoA, nicotinamide adenine dinucleotide or NAD, and lipoic acid.