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Listed below are a number of functional
groups in a variety of biochemical molecules. Many of the functional
groups will be either the reactants or products
in biochemical reactions. As you examine the structures in the
table below, remember:
* An R- group attached to a C, S or N is called a
side chain, or group.
* When the side chain is attached to a C=O as in R-C=O,
such a group is called an ACYL group.
* When R is attached to a C, it is called an ALKYL
group.
After you look at the table, scroll down for more
details about the functional groups.
Details
of Functional Groups
|
Group
|
Written
as...
|
Additional
Information
|
| Alcohols |
R-CH2-OH (primary)
R2-CH-OH (secondary)
R3-C-OH (tertiary)
|
Sustitution
of additional groups on the carbon atom defines whether the
alcohol is primary, secondary or tertiary. The carbon atom
in these cases is in sp3 hybrid state. |
Aldehydes,
and
Ketones |
R-CHO
R2-C=O
|
The
c arbon atom is double-bonded to oxygen in both cases. The
difference is in substitutions. An aldehyde has an R group
and a H atom. A ketone has both substituents as R groups.
The carbon atom in these cases is in sp2 hybrid state. |
| Acids |
R-C=O
!
OH |
Acids
are able to dissociate into H+ and anions. |
| Acid
Anhydrides |
(R-CO)2O
|
Acid
anhydrides are formed from molecules of similar or different
acids with the elimination of a molecule of water. An example
would the formation of pyrophosphate from two molecules of
phosphoric acid. |
| Esters
|
RCH2-O-COCH3
|
An
ester is formed from an alcohol and an acid with the elimination
of a molecule of water. Physiological examples include formation
of triacyl glycerols from fatty acids and glycerol. |
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