Final answer:
The subject of the question is proteins, which are complex natural polymers made of multiple chains of amino acids called polypeptides. Proteins serve various functions due to their diverse structures and are vital biological macromolecules.
Step-by-step explanation:
The student's question refers to proteins, which are natural polymers consisting of multiple chains of amino acid monomers.
These proteins may have a variety of different types of chains, including alpha (a) and beta (B) chains, indicative of their complex structure.
People sometimes use the term 'polypeptide' as a synonym for these chains, which together form the functional protein molecule.
Proteins are classified based upon their structural complexity into simple, conjugated, and derived proteins.
Each protein's structure is crucial to its function, and its complexity is derived from the ways these polypeptide chains fold and interact with each other.
For example, the protein hemoglobin consists of four polypeptide chains, with two alpha and two beta chains linked together by salt bridges.