The potential energy of organic molecules is most readily available to cells in the form of ATP (adenosine triphosphate).

Here's why:

* ATP is the primary energy currency of cells. It acts like a rechargeable battery, storing and releasing energy for various cellular processes.

* Organic molecules (like carbohydrates, fats, and proteins) contain chemical energy. This energy is released through the breakdown of these molecules in cellular respiration.

* Cellular respiration converts the energy from organic molecules into ATP. This process involves a series of reactions that ultimately produce ATP from ADP (adenosine diphosphate) and inorganic phosphate.

In short, ATP is the immediate and accessible form of energy that cells can readily use to perform their functions.