Why do organisms need energy for growth and repair?

Organisms need energy for growth and repair to build and maintain their body structures and to replace damaged cells.

Energy is a fundamental requirement for all biological processes, including growth and repair. In the context of organisms, growth refers to the increase in size and number of cells, which forms the basis of development. Repair, on the other hand, involves the replacement, restoration, or regeneration of damaged or worn-out cells and tissues. Both these processes are energy-intensive as they involve complex biochemical reactions.

The energy required for growth and repair primarily comes from the food we consume. The food is broken down into simpler substances through the process of digestion. These simpler substances, particularly glucose, are then oxidised in the cells to release energy in a process known as cellular respiration. This energy is stored in the form of adenosine triphosphate (ATP), which is often referred to as the 'energy currency' of the cell. ATP provides the energy needed for various cellular activities, including the synthesis of new cellular materials for growth and the repair of damaged tissues.

For instance, during growth, energy is required to synthesise proteins from amino acids, which are then used to build new cells. Similarly, in the repair process, energy is needed to synthesise new cells that replace the damaged ones. Moreover, energy is also required for the active transport of nutrients and other substances across cell membranes, which is crucial for both growth and repair.

In summary, energy is indispensable for growth and repair in organisms. It fuels the biochemical reactions involved in these processes, enabling organisms to develop, maintain their structures, and recover from damage. Without sufficient energy, these vital processes would be hindered, potentially leading to stunted growth or delayed healing.