21. For each pair of electrons passing from NADH located inside the mitochondria to oxygen, how many ATP molecules can be generated?
A. 1
B. 2
C. 3
D. 4
22. In anaerobic respiration, the final electron acceptor can be
A. oxygen
B. nitrate
C. pyruvate
D. acetyl-CoA
23. Which one of the following is not produced in any of the steps of glycolysis?
A. NAD+
B. NADH
C. ADP
D. ATP
24. The number of ATP molecules produced from one glucose molecule by a bacterium producing lactic acid is
A. greater than producing ethanol
B. lesser than producing ethanol
C. approximately equal to producing ethanol
D. none of these
25. Which of the following is the most complete definition of fermentation?
A. Oxidation of glucose with organic molecules serving as electron acceptors
B. Complete catabolism of glucose to CO2 and HO2
C. Production of energy by substrate-level phosphorylation
D. Production of ethyl alcohol from glucose