Concept:Macromolecules like proteins and nucleic acids rely on specific, directional intermolecular forces to maintain their complex 3D structures.
Formula:Not applicable.
Solution:- In proteins, the partial positive Hydrogen of the amide group (\( \text{-NH} \)) forms strong interactions with the partial negative Oxygen of the carbonyl group (\( \text{-C=O} \)), stabilizing \( \alpha \)-helices and \( \beta \)-sheets.
- In DNA, the nitrogenous base pairs (A-T and C-G) strictly connect via the same type of interaction.
- These directional, relatively strong intermolecular forces are Hydrogen bonds.
Why other options are incorrect:While Van der Waals and standard dipole forces exist, they are too weak and non-directional to primarily dictate these rigid secondary structures. Ionic interactions form salt bridges but are not the primary backbone stabilizers of these specific motifs.
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