Question
In the given pentapeptide, find out an essential amino acid ( Y ) and the sequence present in the pentapeptide: Choose the correct answer from the options given below:
JEE Main
Chemistry
Biomolecules
2026
JEE Main 2026 (28 January Shift 1)
JEE Main Chemistry Question (2026) — Solution
Options
- A. \( array |c|c| (Y) & Sequence \\ Serine & Ser-Asp-Thr-Ala-Gly \\ array \)
- B. \( array |c|c| (Y) & Sequence \\ Serine & Thr-Ser-Asp-Ala-Gly \\ array \)
- C. \( array |c|c| (Y) & Sequence \\ Threonine & Ser-Thr-Asp-Gly-Ala \\ array \)
- D. \( array |c|c| (Y) & Sequence \\ Threonine & Thr-Ser-Asp-Gly-Ala \\ array \)
Answer
D. \( array |c|c| (Y) & Sequence \\ Threonine & Thr-Ser-Asp-Gly-Ala \\ array \)
Step-by-step solution
Among the amino acids present (Serine, Aspartic acid, Glycine, Alanine, and Threonine), only Threonine is classified as an essential amino acid; the others are non-essential or conditionally essential. Therefore, Y = Threonine. Examining the peptide sequence shown in the structure and cross-referencing with the provided options, the sequence is Thr-Ser-Asp-Gly-Ala from N-terminus to C-terminus. The answer is option (4): Y is Threonine with sequence Thr-Ser-Asp-Gly-Ala.
Related: Chemistry — Biomolecules · All PYQ Banks