Functional groups in biochemistry: typical elemental makeup and polarity Most important functional groups in biological molecules share what general feature?

Introduction / Context:
Biomolecular reactivity stems from functional groups such as hydroxyls, carbonyls, carboxylates, amines, amides, and phosphates. Their polarity governs solubility, binding, and catalysis in aqueous environments.

Given Data / Assumptions:

• We consider common moieties in proteins, nucleic acids, carbohydrates, and lipids.
• Focus is on elemental composition and polarity.

Concept / Approach:
Oxygen and nitrogen introduce significant electronegativity differences, creating polar covalent bonds and hydrogen-bonding capacity. Many groups are polar but not necessarily acidic (for example, amide). Thus, the best generalization is that key biological functional groups contain O and/or N and are polar.

Step-by-Step Solution:
List examples: hydroxyl (O), carbonyl (C=O), carboxyl (O and O−), amine/ammonium (N), amide (O and N), phosphate esters (O, P).Recognize their polarity and hydrogen-bonding roles.Select the statement that captures polarity without overclaiming acidity.

Verification / Alternative check:
Protein backbones (amide) are polar; nucleic acid bases contain multiple N and O sites enabling H-bond networks.

Why Other Options Are Wrong:
Not all are acidic; phosphates appear widely but not universally; “only C and H” fails for most biomolecules.

Common Pitfalls:
Equating polarity with charge; many polar groups are neutral at physiological pH.

Final Answer:
Oxygen and/or nitrogen and are polar.