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Multiple Choice
Which molecule is the primary product of the light-independent reactions (Calvin cycle) in photosynthesis?
A
NADPH
B
Glucose ($C_6H_{12}O_6$)
C
ATP
D
Oxygen ($O_2$)
Verified step by step guidance
1
Understand that the light-independent reactions, also known as the Calvin cycle, occur in the stroma of the chloroplast and do not require light directly. These reactions use energy stored in ATP and NADPH, which are produced during the light-dependent reactions.
Recall that the primary purpose of the Calvin cycle is to fix carbon dioxide ($CO_2$) into organic molecules, ultimately producing a carbohydrate molecule.
Recognize that the Calvin cycle involves three main phases: carbon fixation, reduction, and regeneration of the $RuBP$ (ribulose-1,5-bisphosphate) molecule.
In the reduction phase, the energy from ATP and the reducing power of NADPH are used to convert 3-phosphoglycerate ($3$-$PGA$) into glyceraldehyde-3-phosphate ($G3P$), a three-carbon sugar molecule.
Understand that $G3P$ is the primary product of the Calvin cycle. Some $G3P$ molecules are used to regenerate $RuBP$, while others are used to synthesize glucose ($C_6H_{12}O_6$) and other carbohydrates.