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Multiple Choice
Which of the following reactions is a key step in the Calvin Cycle?
A
Carboxylation of ribulose-1,5-bisphosphate
B
Hydrogenation of ethene
C
Dehydration of alcohols
D
Oxidation of alkanes
Verified step by step guidance
1
Understand the Calvin Cycle: The Calvin Cycle is a series of biochemical reactions that occur in the chloroplasts of photosynthetic organisms. It is part of the process of photosynthesis and is responsible for the fixation of carbon dioxide into organic molecules.
Identify the key reaction in the Calvin Cycle: The Calvin Cycle involves several steps, including carbon fixation, reduction, and regeneration of ribulose-1,5-bisphosphate. The key step is the carboxylation of ribulose-1,5-bisphosphate, which is the fixation of CO₂.
Carboxylation of ribulose-1,5-bisphosphate: This reaction involves the enzyme ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO), which catalyzes the addition of CO₂ to ribulose-1,5-bisphosphate, forming 3-phosphoglycerate.
Compare with other reactions: Hydrogenation of ethene, dehydration of alcohols, and oxidation of alkanes are not part of the Calvin Cycle. These reactions are typical in organic chemistry but do not relate to the biochemical processes of photosynthesis.
Conclude the key step: The carboxylation of ribulose-1,5-bisphosphate is the correct answer as it is the essential step in the Calvin Cycle for carbon fixation.