These enzymes serve as promoters, or catalyst s, of chemical reactions. Carbohydrates are the basic fuel molecules of the cell. They contain carbon, hydrogen , and oxygen in approximately equal amounts. Animals, however, obtain their carbohydrates from foods. Once a cell possesses carbohydrates, it may break them down to yield chemical energy or use them as raw material to produce other biomolecules.
Lipids are fatty substances that play a variety of roles in the cell.
Biomolecules of many other types are also found in cells. All these biomolecules, and the cell itself, are in a state of constant change. These active, energy-linked processes of change are collectively called metabolism. One major aim of biochemistry is to understand metabolism well enough to predict and control changes that occur in cells. Biochemical studies have yielded such benefits as treatments for many metabolic diseases, antibiotics to combat bacteria, and methods to boost industrial and agricultural productivity.