Final answer:
The quaternary structure of a protein describes the arrangement of subunits into a whole. It involves multiple polypeptides or protein chains interacting with each other to form a functional protein complex.
Step-by-step explanation:
The quaternary structure of a protein refers to the arrangement of subunits into a whole. It describes how multiple polypeptides or protein chains interact with each other to form a functional protein complex.
For example, hemoglobin is a protein in red blood cells that transports oxygen to body tissues. It has a quaternary structure consisting of four subunits: two alpha chains and two beta chains.
Other examples of proteins with quaternary structure include enzymes that have multiple subunits working together to catalyze a biochemical reaction.