Question

In a condensed schematic representation of dark reaction of photosynthesis given below, steps are indicated by alphabets. Select the option where the alphabets are correctly identified

• A. (a)— Regeneration, (b)— CO₂ fixation, (c)— Reduction, (d)— Phosphorylation
• B. (a)— CO₂ fixation , (b)— Phosphorylation, (c)— Reduction, (d)— Regeneration
• C. (a)— CO₂ fixation , (b)— Phosphorylation, (c)— Regeneration, (d)— Reduction
• D. (a)— CO₂ fixation, (b)— Reduction, (c)— Phosphorylation, (d) — Regeneration

Answer 1

Answer: (B)

The diagram represents the Dark reaction of photosynthesis. The label $A$ refers to fixation of $CO _{2}$ by the enzyme RuBisCo which reacts with the RUBP to form PGA. The label $B$ refers to phosphorylation of PGA to give $1,3$-di PGA. The label $C$ refers to reduction of $1,3$ -di PGA to PGA. The label $D$ refers to regeneration of RUBP which will help to continue the cycle to synthesize the glucose molecule.