Large molecules can be broken down to release
energy. Alternatively, they can be formed to build
cellular structures or store information. In
biological systems there are four major types of
chemical reactions involved in breaking apart and
building molecules:
acid-base or neutralization reactions, which
transfer hydrogen ions between molecules,
redox, or oxidation-reduction reactions, which
transfer electrons between molecules,
hydrolysis reactions, in which molecules react
with H2O to form other molecules, and
condensation reactions, in which molecules react
to form H2O and other molecules.
These types of chemical reactions are described
below.