Ch 14 covers biomolecules — carbohydrates (mono-, di-, polysaccharides), proteins (amino acids, structure levels), enzymes, vitamins, nucleic acids (DNA, RNA), and hormones.
Carbohydrates: monosaccharides (glucose — aldohexose, fructose — ketohexose), disaccharides (sucrose = glucose + fructose), polysaccharides (starch, cellulose, glycogen). Proteins: 20 amino acids linked by peptide bonds. Structure levels: primary (sequence), secondary (α-helix, β-pleated sheet), tertiary (3D fold), quaternary (multiple subunits).
DNA: deoxyribose sugar + phosphate + bases (A, T, G, C). Double helix, A=T and G≡C (H-bonds). RNA: ribose + A, U, G, C. Types: mRNA, tRNA, rRNA. Vitamins: water-soluble (B, C) and fat-soluble (A, D, E, K). Deficiency diseases: scurvy (C), rickets (D), night blindness (A), beri-beri (B₁).
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A reducing sugar has a free anomeric carbon (hemiacetal/hemiketal group) that can open to give an aldehyde/ketone and reduce Tollens'/Fehling's reagent. In sucrose, the anomeric carbons of both glucose (C1) and fructose (C2) are involved in the glycosidic bond, so neither can open. Hence sucrose is non-reducing. Maltose and lactose are reducing because one anomeric carbon remains free.
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