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Multiple Choice
Which of the following statements about the energy yield of aerobic respiration is FALSE?
A
The citric acid cycle produces NADH and FADH$_2$ that are used in the electron transport chain.
B
Oxygen acts as the final electron acceptor in the electron transport chain.
C
Aerobic respiration of one molecule of glucose typically yields about 36-38 ATP molecules.
D
Most of the ATP produced during aerobic respiration is generated during glycolysis.
Verified step by step guidance
1
Step 1: Begin by understanding the process of aerobic respiration. Aerobic respiration is a metabolic pathway that uses oxygen to break down glucose and produce ATP, the energy currency of the cell. It consists of three main stages: glycolysis, the citric acid cycle (Krebs cycle), and oxidative phosphorylation (electron transport chain).
Step 2: Analyze the role of glycolysis in ATP production. Glycolysis occurs in the cytoplasm and breaks down one molecule of glucose into two molecules of pyruvate. It produces a net gain of 2 ATP molecules and 2 NADH molecules. This is a relatively small contribution to the total ATP yield in aerobic respiration.
Step 3: Examine the citric acid cycle. The citric acid cycle occurs in the mitochondria and generates high-energy electron carriers, NADH and FADH$_2$, which are used in the electron transport chain. The cycle itself produces only a small amount of ATP directly (via substrate-level phosphorylation).
Step 4: Understand oxidative phosphorylation and the electron transport chain. This is the stage where most ATP is generated. NADH and FADH$_2$ donate electrons to the electron transport chain, which drives the production of ATP through chemiosmosis. Oxygen acts as the final electron acceptor, forming water.
Step 5: Evaluate the false statement. The statement 'Most of the ATP produced during aerobic respiration is generated during glycolysis' is false because the majority of ATP is produced during oxidative phosphorylation, not glycolysis. Glycolysis contributes only a small fraction of the total ATP yield.