Membranes are made of a fluid double layer of
lipid, with proteins scattered around in it.
The lipid bilayer is made of
phospholipids. They
arrange themselves in a double layer because they have
one end that is attracted to water
while the other end is repelled
.
The membrane controls the way that substances enter
and leave cells.
Carbohydrates may be attached to some of the
proteins. These may act as receptors.
Hydrophilic. This is due to the charged phosphate head being attracted to the small charges on water molecules.Hydrophobic. This is because the fatty acid tails are insoluble in water.