Question

The functional group which is found in amino acid is

• A. $COOH$
• B. $N{H}_3$
• C. $C{H}_3$
• D. both A & B

Answer 1

The correct option is D both A & B

Option (D) is correct. The functional group which is found in amino acid are $COOH$ and $N{H}_3$ (amine group). So every amino acid has a central carbon with a $H$, $R$ group (varies for each amino acid), a carboxylic group and an amine group. These groups are joined to a single (aliphatic) carbon. The carbon directly attached to a carboxyl group is the alpha position, so the amino acids in proteins are all alpha-amino acids.

$H_{2}N-\underset{R}{\underset{|}{\stackrel{H}{\stackrel{|}{C}}}}-COOH$