Phospholipids consist of
two fatty acid chains, a phosphate group and a glycerol group. Phospholipids
are characterized by their hydrophobic--not soluble on water--tails, formed by
the fatty acid chains and hydrophilic--soluble in water--heads. This makes them
ideal for being the main molecule found in cellular membranes.
Glycolipids are lipid
molecules that contain a sugar unit, such as glucose or galactose.
Cholesterol is a lipid
that consists of four hydrocarbon rings attached to a hydroxyl--hydrogen bound
to oxygen--group. The four-ring structure makes cholesterol a steroid, and the
hydroxyl group provides it with the amphipathic property of being both
hydrophilic and hydrophobic. Many cell types and organs have the ability to synthesise triacylglycerols.
Within all cell types, even those of the brain, triacylglycerols are stored as
cytoplasmic 'lipid droplets' enclosed by a
monolayer of phospholipids and hydrophobic proteins.
chemical terms, triacylglycerols consist of the trihydric alcohol glycerol
esterified, almost invariably, with long-chain fatty acids. When the two
primary hydroxyl groups are esterified with different fatty acids, the resulting
triacylglycerol is made.
Hope it helps!
Jan 3rd, 2015
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