객관식
The Calvin cycle makes direct use of ________ to make ________.
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9. Photosynthesis
Calvin Cycle
객관식
In the Calvin cycle, if NADPH begins to run out, which compound would be the first to accumulate?
A
3-phosphoglycerate (3-PGA)
B
fructose-6-phosphate
C
ribulose-1,5-bisphosphate (RuBP)
D
glyceraldehyde-3-phosphate (G3P)
검증된 단계별 안내1
Understand the Calvin cycle: The Calvin cycle is a series of biochemical reactions that occur in the stroma of chloroplasts during photosynthesis. It uses ATP and NADPH produced in the light-dependent reactions to convert carbon dioxide into glucose and other sugars.
Identify the role of NADPH: NADPH is a reducing agent in the Calvin cycle. It provides the electrons needed to reduce 3-phosphoglycerate (3-PGA) into glyceraldehyde-3-phosphate (G3P) during the reduction phase of the cycle.
Analyze the impact of NADPH depletion: If NADPH begins to run out, the reduction phase of the Calvin cycle cannot proceed efficiently. This means that 3-phosphoglycerate (3-PGA) will not be converted into glyceraldehyde-3-phosphate (G3P), leading to the accumulation of 3-PGA.
Consider the sequence of reactions: 3-PGA is an intermediate formed during the carbon fixation phase when ribulose-1,5-bisphosphate (RuBP) reacts with CO₂. Without sufficient NADPH, the cycle cannot progress beyond this intermediate.
Conclude the reasoning: Based on the biochemical pathway, the compound that would accumulate first due to NADPH depletion is 3-phosphoglycerate (3-PGA), as it is directly dependent on NADPH for its conversion into G3P.
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