Condensation reactions link carboxyl groups in proteins and lipids

Steps:

• Condensation polymerization joins monomers by removing water from functional groups.
• Carboxyl (-COOH) groups react with amino (-NH2) to form amide (peptide) bonds in proteins.
• Carboxyl groups react with hydroxyl (-OH) to form ester bonds in triglycerides.
• Carbohydrates like amylose and sucrose form via glycosidic bonds between -OH groups only.

Why D is correct:

• Collagen and globulin are proteins linked by peptide bonds (from carboxyl of one amino acid + amino of another); triglyceride forms via ester bonds (carboxyl of fatty acids + -OH of glycerol).

Why the others are wrong:

• A includes pectin (polysaccharide with glycosidic bonds) and sucrose (disaccharide with glycosidic bond).
• B includes amylose (polysaccharide with glycosidic bonds) and sucrose (glycosidic bond).
• C includes amylose (glycosidic bonds) and sucrose (glycosidic bond); globulin is correct but others aren't.

Final answer: D