Hydrolysis adds water across a link rather than merely separating unchanged fragments. A glycosidic link between labelled glucose residues regenerates hydroxyl groups on the glucose units. Each C6H10O5 repeating unit in an ideal long glucose polysaccharide corresponds to aC6H12O6 glucose monomer after hydrolysis; a finite chain also has end groups.
For a peptide –CO–NH– link, restore carboxyl and amino groups, then apply the specified acidic or alkaline conditions. Read each amino-acid side chain without rearranging it. A triglyceride contains three ester-linked fatty-acid residues on glycerol. Restore –COOH on each acyl residue in acidic hydrolysis. The carbonyl carbon remains part of the fatty acid, not the glycerol.
Example 1
Hydrolyse H2NCH(CH3)CONHCH2COOH to neutral amino-acid formulae, ignoring their aqueous acid–base forms.
Split the C(=O)–N link and add OH to its carbonyl carbon and H to nitrogen. Products are H2NCH(CH3)COOH (alanine) and H2NCH2COOH (glycine). The CH3 and H side chains remain on their original α−carbons.
Example 2
A triglyceride has acyl residues C15H31CO–, C15H31CO– and C17H33CO–. Identify its acidic hydrolysis products.
The products are glycerol, two C15H31COOH molecules and one C17H33COOH molecule per triglyceride. The –CO– carbonyl belongs to each fatty acid. Three H2O molecules are consumed.
Watch out:Link formation removes groups such as H and OH; hydrolysis restores them from water, producing the complete monomer.
Biomolecule structures to hydrolysis products practice | Year 12 Chemistry | Ascent Arcade