Q. Which one of the structures given below correctly represents the structural formula of the basic amino acid?
A) HOCH₂–CH₂–CH₂–NH₂
B) H₂N–CH(COOH)–CH₂–CH₂–CH₂–CH₂–NH₂
C) H₂N–CH(COOH)–CH₂–CH₂–COOH
D) H₂N–CH(COOH)–CH₂–OH
Explanation
[Solution from source] Lysine, H₂N–CH(COOH)–(CH₂)₄–NH₂, carries an extra amino group in its side chain, which makes it a basic amino acid. The structure with an extra –COOH in the side chain is glutamic acid (acidic), the one with –CH₂OH is serine (neutral), and HOCH₂–CH₂–CH₂–NH₂ is not an amino acid at all. Answer (2).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.