An active transport proton pump drives protons out of the cell using energy from ATP. Under some circumstances pumps like this can be run in reverse. If this pump could be reversed, what would be the result in the cytoplasm?

Option A, A decrease in pH and an increase in ATP.

Explanation:

Options for the question

1. A decrease in pH and an increase in ATP.

2. An increase in pH and an increase in ATP

3. An increase in H+ concentration and an increase in ADP.

4. A decrease in H+ concentration and a decrease in ATP.

5. An increase in the electrochemical gradient.

Solution

An active proton pump acts is responsible for transporting protons through the inter membrane space. This process is supported by a) Proton concentration gradient which initiates transfer of hydrogen ion from region of lower concentration to region of higher concentration and b) input energy in the form of ATP.

When this process reverses, hydrogen ion is starts moving from region of higher concentration to lower concentration due to which energy input in the form of ATP reduces.  

Thus ATP increases and pH decreases

Option A is correct