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Cellular and Molecular Biology

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Chloroplast Food Production

CELLS-KX7RRP

Chloroplasts utilize water and light to produce molecular oxygen. They utilize carbon dioxide to produce sugars.

The process by which chloroplasts produce sugars is called the

.

This process is

and has three reaction steps: fixation, reduction and regeneration.

The first step utilizes inorganic carbon dioxide and involves the carboxylation of ribulose-1,5-bisphosphate to produce 3-phosphoglyceric acid. This reaction is catalyzed by the enzyme,

.

In the second step,

, the energy carriers produced during light-dependent photosynthesis, are used to reduce 3-phosphoglyceric acid to glyceraldehyde 3-phosphate.

This step involves two reactions:
Firstly, 3-phosphoglyceric acid is

by the enzyme phosphoglycerate kinase and ATP, producing ADP and 1,3-bisphosphoglycerate.

Secondly, 1,3-bisphosphoglycerate is reduced by the enzyme glyceraldehyde 3-phosphate dehydrogenase and NADPH yielding NADP+ and glyceraldehyde 3-phosphate. Some of these glyceraldehyde 3-phosphates are utilized to produce

.

The third step involves a series of reactions to regenerate

.