Q.36 In general, which one of the following statements is NOT CORRECT?
(A) Hydrogen bonds result from electrostatic interactions
(B) Hydrogen bonds contribute to the folding energy of proteins
(C) Hydrogen bonds are weaker than van der Waals interactions
(D) Hydrogen bonds are directional

Hydrogen bonds are key non-covalent interactions in biochemistry, often tested in exams like CSIR NET or GATE. The incorrect statement is option (C).

Option Analysis

Hydrogen bonds arise primarily from electrostatic attraction between a partially positive hydrogen (bonded to N, O, or F) and a partially negative electronegative atom.​

• (A) Correct: Hydrogen bonds result from electrostatic interactions between permanent multipoles, making this the dominant force.​

• (B) Correct: Hydrogen bonds contribute to the folding energy of proteins by stabilizing secondary structures like alpha helices and beta sheets.​

• (C) Not correct: Hydrogen bonds are stronger than van der Waals interactions; typical H-bond energy is 10-40 kJ/mol, while van der Waals is 0.4-4 kJ/mol.​

• (D) Correct: Hydrogen bonds are directional, requiring optimal geometry (often near 180° for donor-H-acceptor angle).​

Hydrogen bonds play a crucial role in molecular biology, from DNA base pairing to protein folding. This article analyzes the question: “In general, which one of the following statements is NOT correct?” focusing on hydrogen bonds’ electrostatic interactions, contribution to protein folding energy, comparison with van der Waals forces, and directionality. Perfect for biotech researchers and exam aspirants.

Core Properties of Hydrogen Bonds

Hydrogen bonds form when a hydrogen atom covalently bonded to electronegative atoms (N, O, F) interacts electrostatically with another electronegative atom’s lone pair. The primary force is electrostatic, including dipole-dipole and polarization effects.​

Typical strength ranges 10-40 kJ/mol, far exceeding van der Waals (London dispersion) forces at 0.4-4 kJ/mol. In proteins, they stabilize alpha-helices and beta-sheets, contributing significantly to folding free energy alongside hydrophobic effects.​

Why Option C is Incorrect

The statement “Hydrogen bonds are weaker than van der Waals interactions” reverses reality. Van der Waals forces are the weakest non-covalent interactions, while hydrogen bonds rank stronger, just below ionic bonds but above dipole-dipole forces. This distinction matters in enzyme kinetics and biomolecular stability your research likely explores.​

Applications in Biotechnology

In genetic engineering and immunology, hydrogen bonds dictate antibody-antigen specificity. Their directionality ensures precise recognition, vital for techniques like PCR and ELISA in your lab work.​

Understanding these clarifies why H-bonds drive processes like DNA melting (ΔG=ΔH−TΔS, where H-bond breakage contributes to $\Delta H$).​