Question

Amino acids are substituted methanes. What are the four substituent groups occupying the four valency positions?

• A. Hydrogen, carboxyl group, amino group and a variable group (R)
• B. Two carboxyl groups, amino group and OH
• C. Two hydrogen, one carboxyl group, amino group and a variable group (R)
• D. Two amino groups, one hydrogen and one carboxyl group

Answer 1

Answer: (A)

The four substituent groups occupying the four valency positions in an amino acids are hydrogen, carboxyl group, amino group and a variable group designated as $R$-group.