[单选题]
Which type of reaction is occurri
+ y*shf40eug zng in this light-independent
kdumye3k.ei/c:m;kqk0u:7 g6 5 nec f reaction of photosynthesis?
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A. Reduction of glycerate 3-phosphate
B. Regeneration of ribulose bisphosphate
C. Photolysis of water
D. Carboxylation of ribulose bisphosphate
参考答案:
D
本题详细解析:
D
Carbon fixation is a light-independent reaction where carbon dioxide reacts with ribulose bisphosphate to form two molecules of glycerate 3-phosphate. This is known as the carboxylation of ribulose bisphosphate.
In this diagram, the product on the right-hand side of the equation is glycerate 3-phosphate, hence, it is not the reduction of glycerate 3-phosphate (Choice A). Reduction of glycerate 3-phosphate would require glycerate 3-phosphate to be a reactant on the left-hand side of the equation which would then get reduced to form triose phosphate.
Similarly, in this diagram, the reactant on the left-hand side of the equation is ribulose bisphosphate, hence, it is not the regeneration of ribulose bisphosphate (Choice B). If this diagram were showing the regeneration of ribulose bisphosphate, triose phosphate would be on the left and ribulose bisphosphate, the product, would be on the right.
Photolysis of water (Choice C) involves light and happens in the first part of photosynthesis. However, in this diagram, it has been indicated that it is a light-independent reaction.
