Biomolecules in the Cell > Proteins - Classification of Amino Acids

Amino acids are the building blocks of ____________.

Amino acids are classified as acidic, basic or neutral depending upon the relative number of amino and carboxyl groups in their molecule. Which of the following are acidic?

(i)

\[\begin{array}{cc}
\ce{(CH3)2CH - CH - COOH}\\
\phantom{..}|\\
\phantom{.....}\ce{NH2}
\end{array}\]

(ii)

\[\begin{array}{cc}
\ce{HOOC - CH2 - CH2 - CH - COOH}\\
\phantom{............}|\\
\phantom{...............}\ce{NH2}
\end{array}\]

(iii)

\[\ce{H2N - CH2 - CH2 - CH2 - COOH}\]

(iv)

\[\begin{array}{cc}
\ce{HOOC - CH2 - CH - COOH}\\
\phantom{.....}|\\
\phantom{........}\ce{NH2}
\end{array}\]

Give a reason for the following observations:

Amino acids behave like salts.

How do you explain the amphoteric behaviour of amino acids?

Draw the zwitter ion structure for sulphanilic acid.

The functional group which is found in amino acids is:

Assertion: Glycine must be taken through diet.

Reason: It is an essential amino acid.

Define the following term as related to proteins:

Primary structure