Metabolism is the set of chemical reactions that occur in living organisms to maintain life. These processes allow organisms to grow and rproduce, maintain their structures, and respond to their environments. Metabolism is usually divided into two categories.

Catabolic Reactions:
breaks down organic matter, for example to harvest energy in cellular respiration

Anabolic Reactions:
use energy to construct components of cells such as proteins and nucleic acids

05-01_metabolism_1.jpg