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Unit 5 - Biological Molecules I
Like organic molecules, biological molecules are
grouped into families. There are four major families of
biological molecules, including proteins, nucleic
acids, carbohydrates, and lipids. The lipids are the
subject of this unit. Of these four families, the lipids
are the structurally the most diverse. This is because
unlike members of the other three families, members
of this families do no share a common structural
feature, but rather share a common physical property;
the are hydrophobic.…read more
Lipids are hydrophobic, nonpolar molelcules.
· They are soluble in nonpolar solvent.
· They are insoluble in polar solvents, such as water
They are isolated from the other biological molecules by
extracting them with nonpolar solvents.
The types of lipids that we will look at include.
· Fatty Acids
· In the carboxylic acid family
· Fatty Acids + Alcohols
· 3 Fatty acids + glycerol
· Phospholipids and glycolipids
· 2 fatty acids + glycerol + phosphate + X
· Derivatives of cholesterol
· Derivatives of the Fatty acid arachidonic acid
· Formed from phospholipids and glycolipids…read more
Fatty acids contain a carboxylic acid group
· This should make them quite polar
However, they also contain a long hydrocarbon tail
· Which overall, makes them nonpolar.