BIOMOLECULES AND ENZYMES

Detailed explanation-1: -Larger proteins that consist of two or more polypeptide chains also contain a fourth level of structure called quaternary structure. Quaternary structure refers to the interactions between the different polypeptides that make up the protein. The simplest case of a protein with quaternary structure is a dimer.

Detailed explanation-2: -Quaternary structure is the interaction of two or more folded polypeptides. Many proteins require the assembly of several polypeptide subunits before they become active. If the final protein is made of two subunits, the protein is said to be a dimer.

Detailed explanation-3: -However, some proteins are made up of multiple polypeptide chains, also known as subunits. When these subunits come together, they give the protein its quaternary structure.

Detailed explanation-4: -Examples of proteins with quaternary structure include hemoglobin, DNA polymerase, ribosomes, antibodies, and ion channels.

Detailed explanation-5: -There are two major categories of proteins with quaternary structure-fibrous and globular. Fibrous Proteins: Actually, the final beta-pleated sheet structure of silk is the result of the interaction of many individual protein chains.