PolymersPolymers are large molecules composed of many similar smaller molecules linked together. The individual smaller molecules are called monomers. When small organic molecules are joined together, giant molecules are produced. These giant molecules are known as macromolecules.
Generally speaking, all macromolecules are produced from a small set of about 50 monomers. Different macromolecules vary because of the arrangement of these monomers. By varying the sequence, an incredibly large variety of macromolecules can be produced. While polymers are responsible for the molecular "uniqueness" of an organism, the common monomers mentioned above are nearly universal.
The variation in the form of macromolecules is largely responsible for molecular diversity. Much of the variation that occurs both within an organism and among organisms can ultimately be traced to differences in macromolecules. Macromolecules can vary from cell to cell in the same organism, as well as from one species to the next.
Polymers: Biological MacromoleculesThere are four basic kinds of biological macromolecules. They are carbohydrates, lipids, proteins and nucleic acids. These polymers are composed of different monomers and serve different functions.
Carbohydrates - composed of sugar monomers and necessary for energy storage.
- Lipids - include fats, phospholipids and steroids. Lipids help to store energy, cushion and protect organs, insulate the body and form cell membranes.
- Proteins - composed of amino acid monomers and have a wide variety of functions including molecular transport and muscle movement.
- Nucleic Acids - include DNA and RNA. Nucleic acids contain instructions for protein synthesis and allow organisms to transfer genetic information from one generation to the next.