Why does a cell need energy?

Cells need energy to carry out essential functions such as growth, repair, and reproduction. This energy is primarily obtained from adenosine triphosphate (ATP), which serves as the energy currency in cells. By breaking down glucose and other nutrients through processes like cellular respiration, cells convert stored energy into a readily usable form, enabling them to perform tasks like muscle contraction, nerve impulse transmission, and the synthesis of macromolecules. In addition to sustaining cellular activities, energy is vital for maintaining homeostasis. Cells must constantly transport ions and molecules against their concentration gradients, power the machinery needed for movement, and regulate their internal environment. Without a steady supply of energy, cells would become dysfunctional and ultimately fail to survive.