Adenosine triphosphate (ATP) is a molecule that serves as the primary energy carrier in all living cells. It consists of three phosphate groups, a ribose sugar, and an adenine base. When ATP is broken down into adenosine diphosphate (ADP) and a free phosphate, energy is released, which cells use for various functions, such as muscle contraction and biochemical reactions. ATP is produced mainly in the mitochondria of cells through processes like cellular respiration and photosynthesis in plants. It is essential for maintaining cellular activities and supporting life, making it a crucial component in the metabolism of all organisms, including humans, plants, and animals.