In how many phases does metabolism occur?

Metabolism occurs in two primary phases: catabolism and anabolism.

In the catabolic phase, organisms break down larger molecules into smaller units, releasing energy in the process. This phase is crucial for producing the energy needed for cellular functions by converting food into usable energy, primarily in the form of ATP (adenosine triphosphate).

Anabolism, on the other hand, involves the synthesis of complex molecules from simpler ones. This phase requires energy input as it builds up the structures of cells and tissues, such as proteins, nucleic acids, and carbohydrates, which are essential for growth, repair, and maintenance of tissues.

These two processes are interconnected, with the energy produced during catabolism being utilized efficiently in anabolism, highlighting the balance that these two phases maintain within metabolic pathways. Understanding this foundational aspect of metabolism is essential for fields involving biochemistry, nutrition, and health sciences.