During photosynthesis when PGA is changed into phosphoglyceraldehyde which of the following reaction occur :a)Oxidationb)Reductionc)Electrolysisd)HydrolysisCorrect answer is option 'B'. Can you explain this answer?

Question

Answer

The conversion of PGA (3-phosphoglycerate) into phosphoglyceraldehyde (PGAL or G3P, glyceraldehyde-3-phosphate) is the sixth step of the Calvin cycle of photosynthesis, and it involves the reduction of PGA by NADPH and ATP. The reaction can be written as:

PGA + NADPH + H+ + ATP → PGAL + NADP+ + ADP + Pi

This reaction is catalyzed by the enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH), which uses the reducing power of NADPH to add a phosphate group to PGA and then remove a hydride ion from the molecule, producing PGAL. This reaction is also known as the reduction phase of the Calvin cycle, as it involves the transfer of electrons from NADPH to PGA, reducing it to PGAL, which can then be used to make glucose or other organic molecules.

Answer

3-phosphoglycerate (PGA, a carboxylic acid) is first phosphorylated into 1,3-bisphosphoglycerate by enzyme 3-phosphoglycerate kinase. This is followed by reduction of 1,3-bisphosphoglycerate catalyzed by glyceraldehyde 3-phosphate dehydrogenase enzyme into glyceraldehyde 3-phosphate (aldehyde). NADPH serves as electron donor here. Thus, the correct answer is B.

Answer

Reduction is the second process in dark reaction, where 3- PGA is first phosphorylated to 1, 3-biphosphoglycerate in the presence of an enzyme phosphoglycerokinase. Then 1, 3-biphosphoglycerate is reduced to glyceraldehyde 3- phosphate in the presence of NADPH.  Thus, option B is correct answer..

Answer

3-phosphoglycerate (PGA, a carboxylic acid) is first phosphorylated into 1,3-bisphosphoglycerate by enzyme 3-phosphoglycerate kinase. This is followed by reduction of 1,3-bisphosphoglycerate catalyzed by glyceraldehyde 3-phosphate dehydrogenase enzyme into glyceraldehyde 3-phosphate (aldehyde). NADPH serves as electron donor here. Thus, the correct answer is B.

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