Chapter 8, Problem 21A

Summary Introduction

Introduction :

ATP and NADPH is known as assimilatory power. It is produced during light-dependent reactions of the photosynthesis. These reactions occur on the thylakoids of chloroplast. The chlorophyll molecules absorb sunlight and covert light energy into assimilatory power in the form of the electron carrier molecule nicotinamide adenine dinucleotide phosphate (NADPH) and the ATP. NADH and ATP is used in light−independent reactions or Calvin cycle to reduce carbon dioxide into carbohydrate.

Answer to Problem 21A

Correct answer :

The correct answer is option (B) ATP and NADH.

Explanation of Solution

Explanation/justification for the correct answer :

Option (B). During Light-dependent reactions of the photosynthesis the chlorophyll molecules absorb sunlight and convert light energy into ATP and NADH which supplies energy used to synthesize carbohydrate during Calvin cycle. Thus, the correct answer is an option (B).

The explanation for the incorrect answer :

Option (A) CO₂ and ATP. CO₂ is reduced to carbohydrate during Calvin cycle using ATP. Thus, this is an incorrect option.

Option (C) NADH and H₂O. NADH is produced during light-dependent reactions and photolysis of H₂O takes place. Thus, this is an incorrect answer.

Option (D) H₂O and O₂. H₂O and O₂ do not supply energy to synthesize carbohydrate during Calvin cycle. Thus, this is an incorrect answer.