Identify the name of the amino acid representing the following structure
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → Tryptophan
All α-amino acids share the unit \( \ce{H2N-CH(R)-COOH} \) and differ only in the side chain R, so an amino acid is identified from its side chain. In the given structure the side chain is a \( \ce{CH2} \) group joined to an indole ring: a benzene ring fused to a five-membered ring that contains an N–H group.
The amino acid with the indole side chain is tryptophan (Trp, W), one of the essential amino acids.
NCERT (2026-27 edition):
Amino Acids – …
