ATP, or adenosine triphosphate, is a molecule that serves as the primary energy currency in all living cells. It is often referred to as the "energy powerhouse" because it stores and transports energy within cells. When cells need energy for activities like muscle contraction or cell division, they break down ATP, releasing the energy stored in its chemical bonds. In addition to providing energy, ATP is also involved in various biochemical processes, including metabolism and signal transduction. It plays a crucial role in synthesizing proteins and nucleic acids, making it essential for growth and repair in living organisms. Without ATP, life as we know it would not be possible.