Nucleic acids are responsible for storing and transferring genetic information. They are enormous molecule s made up of long strands of subunits, called bases, that are arranged in a precise sequence. Proteins are large molecules built up of small subunits called amino acids . Using only 20 different amino acids, a cell constructs thousands of different proteins, each of which has a highly specialized role in the cell. 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.