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NEET-UG and JEE Main Chemistry · Class 12

Protein structure and denaturation — NEET & JEE Questions

Protein structure and denaturation is a topic in Biomolecules, a Class 12 Chemistry chapter of the NEET-UG and JEE Main syllabus. TestBudy holds 12 published NEET-UG and JEE Main questions on Protein structure and denaturation, each with the marking scheme of the real paper.

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Protein structure and denaturation MCQs with solutions

10 of the 12 published questions on this topic, exactly as they appear in a test. Answers and worked solutions come with your result rather than on this page.

  1. Question 1 · difficulty L1 · recall

    The primary structure of a protein refers to

    • A. the amino-acid sequence
    • B. the local alpha-helix only
    • C. the overall three-dimensional folding only
    • D. association of multiple subunits only
  2. Question 2 · difficulty L2 · understanding

    Alpha-helices and beta-pleated sheets are examples of

    • A. primary structure
    • B. secondary structure
    • C. tertiary structure
    • D. quaternary structure only
  3. Question 3 · difficulty L2 · understanding

    The tertiary structure of a protein describes

    • A. the overall three-dimensional folding of a single polypeptide chain
    • B. only the peptide-bond sequence
    • C. the number of amino acids only
    • D. only interactions between separate protein molecules
  4. Question 4 · difficulty L2 · understanding

    Denaturation of a protein usually disrupts

    • A. secondary and tertiary structure more readily than primary peptide-bond sequence
    • B. all peptide bonds immediately
    • C. the identities of all amino acids
    • D. the carbon atoms of the backbone
  5. Question 5 · difficulty L3 · application

    A protein loses biological activity after heating, but analysis shows its peptide bonds remain intact. What most likely occurred?

    • A. Denaturation
    • B. Complete hydrolysis
    • C. Polymerisation
    • D. Formation of additional peptide bonds
  6. Question 6 · difficulty L3 · application

    Which interaction is commonly important in stabilising protein secondary structure?

    • A. Hydrogen bonding
    • B. Metallic bonding only
    • C. Ionic lattice bonding throughout the backbone
    • D. C-C bond cleavage
  7. Question 7 · difficulty L3 · application

    A protein consisting of several polypeptide chains assembled into one functional unit displays

    • A. primary structure only
    • B. secondary structure only
    • C. quaternary structure
    • D. no higher-order structure
  8. Question 8 · difficulty L3 · application

    Which treatment is most likely to denature a typical protein?

    • A. Strong heating
    • B. Keeping it under mild physiological conditions
    • C. Maintaining its normal pH and temperature
    • D. Providing its usual solvent environment
  9. Question 9 · difficulty L4 · application

    A protein is treated with a reagent that disrupts hydrogen bonds and hydrophobic interactions but does not cleave peptide bonds. Which structural levels are most directly affected?

    • A. Secondary and tertiary structures
    • B. Primary structure only
    • C. Only amino-acid composition
    • D. No structural level
  10. Question 10 · difficulty L4 · application

    Which statement correctly distinguishes denaturation from hydrolysis of a protein?

    • A. Denaturation disrupts higher-order folding, while hydrolysis cleaves peptide bonds
    • B. Denaturation always changes amino-acid identities, while hydrolysis does not
    • C. Both processes are identical
    • D. Hydrolysis affects only quaternary structure

Common mistakes in Protein structure and denaturation

Recorded against questions in this topic that are not shown above, so none of these points at an answer you can see on this page.

  • Assumes any change in shape implies a change in amino-acid sequence.
  • Uses the loss of biological activity alone to conclude that peptide bonds must have been cleaved.

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