6. Which of the following is not a feature of oxidative phosphorylation?

A. Direct transfer of phosphate from a substrate molecule to ADP
B. An electrochemical gradient across the inner mitochondrial membrane
C. A membrane bound ATP synthase
D. A protonmotive force

7. Which of the following is not a significant biological oxidizing agent?

A. FAD
B. Fe³⁺
C. O₂
D. NAD⁺

8. How many CO₂molecules are exhaled for each O₂molecule utilized in cellular respiration?

A. 1
B. 3
C. 6
D. 12

9. What happens after glycolysis when oxygen is available as an electron acceptor?

A. Pyruvate is formed
B. NADH is produced
C. Fermentation
D. Oxidative phosphorylation

10. Lactic acid is produced by human muscles during strenuous exercise because of lack of

A. oxygen
B. NAD⁺
C. glucose
D. ADP and P_i