Organisms need energy to maintain their internal order, or homeostasis. For example, plants need energy from sunlight to convert carbon dioxide and water into glucose (sugar) and oxygen in a process called photosynthesis. Animals need energy to move, to pump blood, and to digest food. Get more info at iProMTG
Energy is also needed to make new cells, repair damaged ones, and support the many chemical reactions that take place in the body. These reactions include those that break down food into nutrients that can be used by the cells, and those that make the molecules needed for new cell growth.
ATP
Adenosine triphosphate (ATP) is the main source of energy for most cellular processes. It is a small molecule that consists of adenine (one of the four bases that make up DNA and RNA), ribose (a sugar), and three phosphate groups. ATP stores energy in its bonds between the phosphate groups. When these bonds are broken, ATP releases energy that can be used by the cell.
ATP + H2O + ADP + Pi
The above reaction is an example of hydrolysis. Hydrolysis is the process of breaking a chemical bond using water. In this case, the bond between the second and third phosphate groups in ATP is broken, and a water molecule (H2O) is added. This process releases energy that the cell can use.
ATP + H2O + ADP + Pi + energy
ATP can be recycled back to its original form, ATP, using the energy released from the hydrolysis of other molecules, such as glucose.
Glucose + oxygen + carbon dioxide + water + energy
The above reaction is called cellular respiration. In cellular respiration, glucose and oxygen are combined to form carbon dioxide, water, and ATP. The energy released from the hydrolysis of ATP is used to recycle ATP back to its original form.
ATP + H2O + ADP + Pi + energy
The energy released from the hydrolysis of ATP is used to power many cellular processes, such as muscle contraction, nerve impulse conduction, and active transport.