AP BIOLOGY

Detailed explanation-1: -The quaternary structure of a protein is the association of several protein chains or subunits into a closely packed arrangement. Each of the subunits has its own primary, secondary, and tertiary structure. The subunits are held together by hydrogen bonds and van der Waals forces between nonpolar side chains.

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: -The quaternary structure describes the arrangements of subunits in a protein that contains more than one subunit. Four major types of attractive interactions determine the shape and stability of the folded protein: ionic bonding, hydrogen bonding, disulfide linkages, and dispersion forces.

Detailed explanation-4: -The quaternary structure is held together by a combination of Hydrogen bonds, disulphide bridges and Ionic bonds. They often also contain an inorganic group called a prosthetic group. An example of a quarternary protein that contains the prosthetic Haem group is Haemoglobin.

Detailed explanation-5: -Quaternary structure 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.