2008/9 Schools Wikipedia Selection. Related subjects: Health and
medicine Lipids are broadly defined as any fat-soluble (
lipophilic), naturally-occurring molecule, such as fats, oils,
waxes, cholesterol, sterols, fat-soluble vitamins (such as
vitamins A, D, E and K), monoglycerides, diglycerides,
phospholipids, and others. The main biological functions of
lipids include energy storage, acting as structural components
of cell membranes, and participating as important signaling
molecules. Although the term lipid is sometimes used as a
synonym for fats, fats are a subgroup of lipids called
triglycerides and should not be confused with the term fatty
acid. Lipids also encompass molecules such as fatty acids and
their derivatives (including tri-, di-, and monoglycerides and
phospholipids), as well as other sterol-containing metabolites
such as cholesterol. The emulsion test is a crude method for
determining the presence or absence of lipids in a given sample.
Lipids are a diverse group of compounds that have many