Video Transcript
Part of the basic structure of an
amino acid is provided. Give the molecular formula of the
functional group that is missing.
Amino acids are monomers, or
building blocks, that bind together into peptides. Peptides then fold into specific
configurations to form proteins. Proteins are a class of
macromolecules with diverse forms and functions, including enzymes, immune
components, and signaling molecules. Now, let’s look at the basic
structure of an amino acid so we can identify the functional group that is missing
from the diagram.
The central carbon in an amino acid
is called the 𝛼-carbon. You likely already know that a
carbon atom can form four bonds. One of the bonds is between the
𝛼-carbon and the R group, sometimes called the side chain. The R group varies between
different amino acids, giving them their specific chemical properties. For example, small differences in
the R group can change an amino acid from acidic to basic or from polar to
nonpolar.
The other three functional groups
are the same for all amino acids. The second bond connects the
𝛼-carbon to an amino group. The third binds the carbon to a
hydrogen atom. And the fourth connects the carbon
to a carboxyl group. The carboxyl group is the
functional group that is missing from the diagram we were given. A carboxyl group has a carbon bound
to an oxygen atom and a hydroxyl group.
So, the correct molecular formula
for the missing functional group is COOH.
