Question

The mechanism of phosphorylation is depicted in the diagram below. Study it carefully and mark the correct option.

• A. The diagram depicts photosynthetic phosphorylation taking place in the chloroplast. The incident light should be shown in the diagram.
• B. The diagram depicts oxidative phosphorylation taking place in mitochondria. However, the flow of electrons should be shown in the reverse direction.
• C. Diagram depicts the basic process of both oxidative as well as photosynthetic phosphorylation. However, the proton concentration should be high inside and low outside.
• D. The diagram correctly depicts the oxidative phosphorylation occuring in all heterotrophic organisms.

Answer 1

The correct option is B The diagram depicts oxidative phosphorylation taking place in mitochondria. However, the flow of electrons should be shown in the reverse direction.

As, shown in the diagram, $NADH$ formed in the kreb cycle are used to generate electrons and these electrons are transported across the membrane ultimately to oxidise $H_2$ into $H_{2}O$. This whole process creates a proton gradient across the membrane. This proton gradient initiates the Chemiosmosis process that leads to the formation of ATP.

But, the image given in the question depicts the oxidative phosphorylation in which the production of $NADH$ and $O_2$ takes place. Thus, the direction of flow of electrons shloud be in reverse direction.

So, the correct answer is (B).