NEET BIOLOGY

Detailed explanation-1: -Sedoheptulose-1, 7-bisphosphate (SBP) and sedoheptulose-7-phosphate (S7P) are seven-carbon metabolites in the light-independent stage of photosynthesis. SBP is generated from the transfer of DHAP, the three-carbon metabolite, to the four-carbon metabolite, E4P, which is catalyzed by transaldolase.

Detailed explanation-2: -Carbon fixation, the incorporation of carbon dioxide into an organic molecule, is the first step of the light independent process. To form one molecule of glucose, 6 molecules of CO2 bind with Ribulose Bisphosphate (RuBP). This reaction is catalyzed by the enzyme ribulose biosphosphate carboxylase/oxidase (RUBISCO).

Detailed explanation-3: -Ribulose-1, 5-bisphosphate carboxylase/oxygenase (RuBisCO) is the key enzyme involved in photosynthetic carbon fixation, as it catalyzes the conversion of atmospheric CO2 into organic compounds.

Detailed explanation-4: -Stage 1: Fixation In the stroma, in addition to CO2, two other components are present to initiate the light-independent reactions: an enzyme called ribulose-1, 5-bisphosphate carboxylase/oxygenase (RuBisCO), and three molecules of ribulose-1, 5-bisphosphate (RuBP), as shown in Figure 13.6.