Which function is primarily associated with ATP in the cell?

The primary function of ATP (adenosine triphosphate) in the cell is to supply energy. ATP serves as the main energy currency of the cell, providing the necessary energy for various biochemical reactions and cellular processes. When ATP is hydrolyzed (broken down), it releases energy that can be utilized for muscle contraction, active transport of molecules across membranes, synthesis of macromolecules like proteins and nucleic acids, and other energy-requiring processes.

In contrast, the other functions listed do not directly relate to ATP's core role. The storage of genetic information is primarily the responsibility of DNA. The transport of oxygen is mainly facilitated by hemoglobin in red blood cells. Regulation of blood pH is controlled through various buffers and physiological processes, not directly by ATP. Thus, while ATP plays a vital role in energy supply, these other options emphasize different biological functions that are not intrinsically tied to ATP itself.