Briefly describe the three stages of CO2 assimilation in pho

Briefly describe the three stages of CO_2 assimilation in photosynthetic organisms.

Solution

Answer:

Photosynthesis is a process, which involves the utilization of the inorganic molecules such as the carbondioxide and water in presence of the sunlight to prepare the food material by plants. During the process of photosynthesis in C3 plants, it involves three major steps.

1) In first step, the Condensation of the carbon-dioxide with Ribulose 1,5 bi phosphate to form two molecules of 3-phosphoglycerate.This reaction takes place in presence of the enzyme RUBISCO ( Ribulose 1,5-bisphosphate carboxylase oxygenase ). Rubisco is the most abundant plant protein in the biosphere. Mg is acting as the activator in the enzyme RUBISCO.

2) In second step, the reduction of the 3-phosphoglycerate to triose phosphate takes place in the presence of the enzymes. In this step, 3-phosphoglycerate is converted to 1,3-bisphosphoglycerate in presence of enzyme kinase and this 1,3-bisphosphoglycerate is further converted to glyceraldehyde 3-phosphate, in presence of enzyme
glyceraldehyde 3-phosphate dehydrogenase. By end of the second step, 12 molecules of the glyceraldehyde 3-phosphate are formed.

3) Third step is regeneration process, out of 12 molecules, 10 molecules of glyceraldehyde 3-phosphate is used to regenerate RUBP (Ribulose 1,5 Biphosphate) and other two partcipate in preparation of sugars such as the monosaccharides (Ribose, Glucose, fructose, and seduheptulose).