Biomolecules NEET PYQs (1996–2026)

Solved Biomolecules PYQs

3 recent questions with answers. The full set of 100 is free to practise.

1. NEET 2026MediumProteins
   Q1

   A protein undergoes reversible thermal denaturation from its initial state N to denatured state D according to N ⇌ D. At $60^{\circ }C$, the concentrations of both N and D are equal at equilibrium, and the standard enthalpy change of denaturation is $666kJmo{l}^{-1}$. The standard entropy change ($\Delta S^{\circ }$ in kJ $K^{-1}mo{l}^{-1}$) of the protein upon denaturation at $60^{\circ }C$ is closest to:

   • A2.0
   • B2000.0
   • C333.0
   • D11.1

   Show answer & solution

   Correct answer: (A)

   At equilibrium,
   
   $\Delta G^{\circ }=0=\Delta H^{\circ }-T\Delta S^{\circ }$.
   
   $$\Delta S^{\circ }=\frac{\Delta H^{\circ }}{T}=\frac{666}{333}=2.0$$
   
   kJ K^-1 mol^-1.
2. NEET 2026EasyNucleic Acids
   Q2

   The correct statement with regard to the secondary structure of DNA/RNA is

   • ARNA possesses a single strand helix structure and
     
     contains thymine as one of the four bases
   • BDNA possesses a double strand helix structure and
     
     contains thymine as one of the four bases
   • CRNA possesses a double strand helix structure and
     
     contains uracil as one of the four bases
   • DDNA possesses a single strand helix structure and
     
     contains uracil as one of the four bases

   Show answer & solution

   Correct answer: (B)

   DNA is double-stranded helix with thymine; RNA is single-stranded with uracil.
3. NEET 2024ModerateEnzymes
   Q3

   Ligases is a class of enzymes responsible for catalysing the linking together of two compounds. Which of the following bonds is not catalysed by it? [NEET 2024 Re ]

   • A$C-C$
   • BP − O
   • C$C-O$
   • D$C-N$

   Show answer & solution

   Correct answer: (A)

   Option (1) is the correct answer because, ligases are the enzymes that catalyse the linking together of 2 compounds, e.g., enzymes which catalyse joining of $C-O,C-S,C-N,P-O$ etc. bonds.
   $\Rightarrow$ Options (2), (3) and (4) are wrong as ligase catalyse the joining of $P-O,C-O\&C-N$ bonds.

Topic-wise question count

Where NEET has asked from Biomolecules, most frequent first.

• Enzymes26
• Proteins21
• Carbohydrates16
• Nucleic Acids15
• Vitamins14
• Lipids4
• Biomolecular Structures3
• proteins1

Year-wise Biomolecules questions in NEET

Number of questions from this chapter in each year's paper(s).