Question

Amino acids have substituent groups occupying the four valency positions of the central carbon atom. The substituents are

• A. two carboxyl groups, two amino groups
• B. hydrogen, carboxyl group, amino group and a variable R group
• C. hydrogen, carboxyl group, amino group
• D. two hydrogen, carboxyl group and amino group

Answer 1

The correct option is B hydrogen, carboxyl group, amino group and a variable R group

Amino acids have four substituent groups occupying the four valency positions of the central carbon atom (alpha carbon). These are hydrogen, carboxyl group, amino group and a variable group designated as R group. So, amino acids are also known as substituted methanes because of the substituent groups.