I. Aromatic amino acid:
Aromatic amino acids such as phenylalanine, tyrosine, and tryptophan are involved in the formation of proteins and metabolic pathways.
Match:D - Tryptophan.
II. Phospholipid:
Phospholipids are major components of biological membranes. They contain a glycerol backbone, two fatty acid chains, and a phosphate group.
Match:A - Lecithin (a type of phospholipid).
III. Heterocyclic compounds:Guanine is an example of a heterocyclic compound, as it contains a nitrogenous ring structure and is a part of nucleic acids.
Match:B - Guanine.
IV. Intracellular ground substance:
The intracellular matrix often contains collagen, which is a structural protein found in connective tissue.
Match:C - Collagen.
