[Campbell Biology P.250] The text compares the Calvin cycle to the citric acid cycle. Which ... | Practice Question
The text compares the Calvin cycle to the citric acid cycle. Which of the following statements accurately describes a key difference between these two processes?
A: The Calvin cycle is catabolic, breaking down molecules, whereas the citric acid cycle is anabolic, building molecules.
B: The Calvin cycle consumes ATP and NADPH, while the citric acid cycle uses oxygen to produce ATP.
C: The Calvin cycle synthesizes sugar from CO2 and is anabolic, whereas the citric acid cycle oxidizes acetyl CoA and is catabolic.
D: Both cycles regenerate a starting material, but only the Calvin cycle occurs in the stroma.
E: The Calvin cycle produces oxygen as a byproduct, while the citric acid cycle produces carbon dioxide.
Explanation
The text explicitly states that 'The Calvin cycle is anabolic, building carbohydrates from smaller molecules and consuming energy,' while 'the citric acid cycle is catabolic, oxidizing acetyl CoA and using the energy to synthesize ATP.' This highlights the fundamental difference in their metabolic roles and energy flow.