Question

Uncouplers of oxidative phosphorylation in mitochondria also uncouple photoelectron transport and ATP synthesis in chloroplasts. Why is that?
a. The use of a similar ATP synthase in oxidative phosphorylation and photosynthesis allows the same molecular targeting to function for both.
b. Mitochondria and chloroplasts have a similar two-membrane structure.
c. Both mitochondria and chloroplasts use a hydrogen ion concentration gradient to synthesize ATP.
d. The redox potentials of NADH and NADPH are similar to each other.

Answer 1

Answer:

a. The use of a similar ATP synthase in oxidative phosphorylation and photosynthesis allows the same molecular targeting to function for both.

Explanation:

Uncouplers are agents capable of corrupting the coupling that exists between ATP synthase and the electron transport chain.

These uncouplers act by dissipating the proton gradient across the inner mitochondrial membrane created by the electron transport system.

The uncouplers are able to act on oxidative phosphorylation, photoeletron transport and ATP due to the fact that the overall structure and catalytic mechanism of chloroplast ATP synthase are virtually the same as those of the mitochondrial enzyme.

The difference is that in chloroplasts, energy synthesis is generated not by the electron transport respiratory chain, but by primary photosynthetic proteins.