Question

Dark reaction in photosynthesis is called so because

• A. it can occur in dark also
• B. it does not directly depend on light energy
• C. it cannot occur during day light
• D. it occurs more rapidly at night

Answer 1

Answer: (B)

it does not directly depend on light energy

Answer 2

Biosynthetic phase (dark or Blackman's reaction) catalyses assimilation of $CO_{2}$ to carbohydrates. The reactions are called carbon reactions.They occur in stroma of chloroplasts. The reactions do not require light. Instead assimilatory power ($ATP$ and $NADPH$) produced during photochemical phase is used in fixation and reduction of carbon dioxide. All the enzymes required for the process are present in the matrix or stroma of the chloroplast.