Intermolecular forces — Hydrogen bonds and hydrophilic interactions are best described as which type of chemical interaction?
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Aweak chemical bonds that hold together the atoms within a molecule
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Bstrong chemical bonds that hold together the atoms within a molecule
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Cweak chemical bonds that link together separate molecules
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Dstrong chemical bonds that link together separate molecules
Answer
Correct Answer: weak chemical bonds that link together separate molecules
Explanation
Introduction / Context:Biological structure depends on both covalent bonds and numerous weaker, reversible interactions. Hydrogen bonds and hydrophilic interactions organize macromolecules, guide folding, and enable molecular recognition in aqueous environments.
Given Data / Assumptions:
- Covalent bonds are strong and intramolecular.
- Hydrogen bonds are directional interactions between a hydrogen donor (e.g., O–H, N–H) and an electronegative acceptor (O, N).
- Hydrophilic interactions reflect favorable hydration and polar contacts.
Concept / Approach:Hydrogen bonds and hydrophilic contacts are typically noncovalent, weaker than covalent bonds, and often operate between separate molecules (intermolecular) or between distant parts of a large macromolecule (effectively linking segments). Their reversibility underlies dynamic biological assemblies.
Step-by-Step Solution:
Classify bond strength: hydrogen/hydrophilic interactions are weaker than covalent.Classify scope: they most commonly link different molecules (e.g., water with solutes, protein–ligand complexes).Select the choice describing weak, intermolecular linkages.Verification / Alternative check:Melting points, boiling points, and protein denaturation studies show disruption of noncovalent interactions at modest energies compared to covalent bond cleavage.
Why Other Options Are Wrong:
- Strong/intramolecular: describes covalent bonds, not hydrogen bonds.
- Strong/intermolecular: overstates the strength of hydrogen/hydrophilic interactions.
- Weak/intramolecular only: they frequently act between separate molecules.
Common Pitfalls:Equating “weak” with “unimportant”; collectively, many weak interactions produce robust structures.
Final Answer:weak chemical bonds that link together separate molecules