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JEE Main · 2022 · 25 Jun 2022 · Shift 2 · Biomolecules

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How many of the given compounds will give a positive Biuret test ______?
Glycine, Glycylalanine, Tripeptide, Biuret

Answer: 2

Solution

The Biuret test is positive for compounds containing at least two peptide linkages (or the biuret structure itself).
  • Glycine: single amino acid, no peptide linkage → negative
  • Glycylalanine: dipeptide, one peptide linkage → negative
  • Tripeptide: has two peptide linkages → positive
  • Biuret: has the characteristic structure with two peptide-like linkages → positive

Therefore, 2 compounds give a positive Biuret test.

JEE Main · 2022 · 25 Jun 2022 · Shift 2 · Integer answer

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