Biomolecule Classification: Carbs and Proteins

Steps:

• Classify each term: carbohydrates include monosaccharides (e.g., fructose), disaccharides (e.g., sucrose), polysaccharides (e.g., cellulose); proteins include collagen; nucleic acids include RNA.
• Identify the pattern: seek one example each of monosaccharide, disaccharide, polysaccharide, and protein.
• Evaluate options: A mixes duplicates and skips disaccharide; B and C introduce nucleic acid; D lists sucrose (disaccharide), cellulose (polysaccharide), fructose (monosaccharide), collagen (protein).
• Confirm D as the only complete, distinct match.

Why D is correct:

• Sucrose (C₁₂H₂₂O₁₁) is a disaccharide formed by glucose and fructose; cellulose is a β-glucose polysaccharide; fructose is a ketohexose monosaccharide; collagen is a triple-helix fibrous protein—distinct biomolecule types per standard biochemistry definitions.

Why the others are wrong:

• A: Duplicates monosaccharides (fructose, glucose) without a disaccharide.
• B: Includes ribonucleic acid (nucleic acid polymer of nucleotides) unrelated to carbs/proteins.
• C: Includes ribonucleic acid and duplicates disaccharides (maltose, sucrose).

Final answer: D