Multiple Choice
Which product of the Krebs cycle is also used as a reactant in the Krebs cycle?
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24. Metabolism and Nutrition
Cellular Respiration: Krebs Cycle
Multiple Choice
Taking one molecule of glucose through glycolysis, pyruvate oxidation, and the Krebs cycle generates:
A
6 CO2, 8 NADH, 2 FADH2 and 4 ATP.
B
6 CO2, 8 NADH, 1 FADH2 and 2 ATP.
C
6 CO2, 10 NADH, 2 FADH2 and 4 ATP.
D
6 CO2, 10 NADH, 2 FADH2 and 2 ATP.
Verified step by step guidance1
Understand the process: Glycolysis, pyruvate oxidation, and the Krebs cycle are stages of cellular respiration that convert glucose into energy, carbon dioxide, and electron carriers.
Glycolysis: This process occurs in the cytoplasm and breaks down one molecule of glucose into two molecules of pyruvate, generating 2 ATP and 2 NADH.
Pyruvate Oxidation: Each pyruvate is transported into the mitochondria and converted into acetyl-CoA, releasing 1 CO2 and producing 1 NADH per pyruvate. Since there are two pyruvates, this results in 2 CO2 and 2 NADH.
Krebs Cycle: Each acetyl-CoA enters the Krebs cycle, which occurs in the mitochondrial matrix. For each acetyl-CoA, 2 CO2, 3 NADH, 1 FADH2, and 1 ATP are produced. Since there are two acetyl-CoA molecules, this results in 4 CO2, 6 NADH, 2 FADH2, and 2 ATP.
Combine the totals: Add the products from all stages. Glycolysis contributes 2 ATP and 2 NADH, pyruvate oxidation contributes 2 CO2 and 2 NADH, and the Krebs cycle contributes 4 CO2, 6 NADH, 2 FADH2, and 2 ATP. This results in a total of 6 CO2, 10 NADH, 2 FADH2, and 4 ATP.
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