Final answer:
The macromolecule that contains a sulphydryl functional group is an amino acid, specifically cysteine, which can form disulfide bonds crucial for protein structure.
Step-by-step explanation:
The macromolecule that contains a sulphydryl functional group is D) Amino acid. The sulphydryl group, denoted as SH, is a functional group consisting of a sulfur atom bonded to a hydrogen atom. This group is characteristic of the amino acid cysteine, where it plays a crucial role in the structure and function of proteins. For instance, two cysteine molecules can react to form a disulfide bond, which is important for the stabilization of protein structure.
Each type of macromolecule, including proteins, lipids, carbohydrates, and nucleic acids, has its own set of functional groups that contribute to its unique chemical properties. Amino acids are the building blocks of proteins, and the presence and reactivity of their functional groups determine the three-dimensional structure and function of the proteins they compose.