Cells replenish ATP supplies by . a. removal of a phosphate group from ADP b. coupling exergonic ATP synthesis with endergonic anabolic reactions c. coupling endergonic ATP synthesis with exergonic catabolic reactions d. coupling spontaneous reactions with ATP hydrolysis e. obtaining energy from enzymes to fuel ATP synthesis

b. coupling exergonic ATP synthesis with endergonic anabolic reactions.  

Explanation:

Adenosine triphosphate or ATP, is the energy carrying molecule that is found in all living cells of organism. The ATP is produced as a chemical energy that is obtained as the process of breakdown of food molecules. When ATP molecule splits into adenosine diphosphate and phosphate it releases energy for cellular metabolism.

The transfer of ATP from one molecule to another results in a coupling chemical reaction. The exergonic reactions are those reactions in which energy is released and endergonic reactions are those reactions which requires energy. In coupled bioenergetic reactions the energy is released through the exergonic reaction or process is utilized to provide the power to the endergonic reaction. These reactions helps in replenishing the ATP molecules. The anabolic pathway requires the building up of the macromolecules which requires break down of ATP molecules.