Final answer:
ATP is a small, relatively simple molecule that acts as the primary energy currency of cells. It stores and releases energy to power cellular reactions and perform cellular work.
Step-by-step explanation:
ATP is a small, relatively simple molecule that acts as the primary energy currency of cells. It stores energy in the bonds between phosphate groups and releases energy when it is broken down into ADP and inorganic phosphate. The energy released from ATP is used to power cellular reactions and perform cellular work.