Question

Suppose you were to add the uncoupler dinitrophenol (DNP) to a preparation of chloroplast carrying out photosynthesis. Which of the following activities would you expect to be affected? (1) absorption of light, (2) cyclic photophosphorylation, (3) electron transport between PSII and PSI, (4) noncyclic photophosphorylation, (5) synthesis of PGA, (6) NADP⁺ reduction

Answer 1

Answer:

The activity which is likely to be affected is Cyclic Phosphorylation

Explanation:

In the Cyclic phosphorylation high energy electron released from P700 returns  to the photosystem 1 via moving through a cycle that contains different acceptors. This type of Transport facilitates the mobility of Hydrogen ions across the cell membrane which eventually generates concentration gradient and helps in the production of ATP while moving Hydrogen ions from lower to higher concentration through the ATP synthetase channel protein on membranes. (DNP) Dinitrophenol acts as protonophore and drives the transfer of Hydrogen ions across the membrane skipping the ATP Synthetase. DNP make cells inefficient to produce ATP molecules for its energy.