There are several atom combinations that show up again and
again in molecules and affect the chemistry of the molecules. These
functional groups are part of the "language" of biological
chemistry, and it can be very useful to have most of them committed
these groups tend to be polar, and it is often the polarity characteristics that
help determine their chemistry:
ALDEHYDE, -C=O on an end carbon.
KETONE, -C=O on an internal carbon.
ACETYL GROUP, end grouping with a ketone just inside an end methyl
METHYL GROUP, -CH3 that can be added or removed to
activate large molecules.
CARBOXYLS, ACID GROUPS, -COOH. These
will generally give up the hydrogen on the end as an ion, adding such H+ ions
to solution, which is why it's an acid.
AMINO GROUPS, -NH2. These
tend to pick up hydrogen ions from solution, making the solution basic.
(MERCAPTANS), -SH. When found
large molecules, loses hydrogens and covalently bonds to other sulfurs,
forming covalent internal bridge-like connections that can help to hold a molecule in
a stable form.
Varies in form according to pH. Commonly moved onto and off
molecules as an energy carrier.
Again, this terminology is used so commonly that it should be part of your