The large molecules comprising the majority of cell components are called macromolecules, or polymers. Polymers are formed when two or more small units called monomers bond together. The bonding between monomers occurs when a hydrogen (H+) is removed from one monomer and a hydroxyl (OH–) is removed from another, creating an electrical attraction between them. Since the components of water (H+ and OH–) are removed (dehydration) in the formation (synthesis) of a bond, the process is referred to as dehydration synthesis. Dehydration synthesis is controlled by an enzyme.
Hydrolysis, which is essentially the opposite of dehydration synthesis, occurs when a hydrogen from water becomes attached to one monomer and a hydroxyl group to the other. Energy is released when a bond is broken by hydrolysis. This energy may be stored temporarily or used in the manufacture or renewal of cell components. Four of the most important classes of polymers found in cells are carbohydrates, lipids, proteins, and nucleic acids.
0 comments:
Post a Comment