Subtopic: Fundamentals of Biomolecules, enzyme kinetics
Question Statement:
In general, which one of the following statements is NOT CORRECT?
Options:
(A) Hydrogen bonds result from electrostatic interactions
(C) Hydrogen bonds are weaker than van der Waals interaction.
(B) Hydrogen bonds contribute to the folding energy of protein:
(D) Hydrogen bonds are directional
Official Answer Key:
C
Step-by-Step Solution & Explanation
### **Official Solution & Concept Analysis (GATE BT 2019 Q.36)**
**1. Governing Concept**:
- **Topic**: Biochemistry & Protein Folding Thermodynamics
- In globular proteins:
- The interior core is packed with non-polar hydrophobic amino acid side-chains (Leu, Ile, Val, Phe), sequestered from aqueous solvent (driven by the **hydrophobic effect**).
- Polar and charged residues (Lys, Arg, Glu, Asp) are predominantly located on the solvent-accessible exterior surface where they participate in favorable electrostatic interactions and hydrogen bonding with water.
**2. Option Analysis**:
- **Option (A) is INCORRECT**: Charged residues are rarely buried in the uncharged interior unless participating in neutral salt bridges.
- **Option (B) is INCORRECT**: Hydrophobic residues are buried, not exposed to water.
- **Option (C) [Hydrophobic residues are buried inside and hydrophilic residues are on the surface] is CORRECT**: The fundamental thermodynamic principle governing native globular protein architecture.
- **Option (D) is INCORRECT**: Reverses interior and exterior residue distributions.
**3. Final Answer**:
- **Correct Choice**: **C**
Practice This in Real CBT Exam Interface
Test yourself with the official TCS-iON palette, virtual calculator, and immediate performance analytics.