Bond formation in lipid macromolecules

Steps:

• Identify the reactants in the diagram: typically glycerol and fatty acids for triglycerides.
• Recognize the reaction as condensation, releasing water.
• Note the linkage between carboxyl group of fatty acid and hydroxyl group of glycerol.
• Confirm the bond type as ester, characteristic of lipid synthesis.

Why A is correct:

• Ester bonds form via dehydration synthesis between carboxylic acids and alcohols, as in triglyceride formation (R-COOH + HO-R' → R-COO-R' + H2O).

Why the others are wrong:

• B: Glycosidic bonds link monosaccharides in carbohydrates, not lipids.
• C: Hydrogen bonds stabilize structures but do not form the polymer backbone.
• D: Peptide bonds join amino acids in proteins via amide linkages.

Final answer: A