Which one of the following polymers is made of protein ?

Polymers are classified based on their chemical composition and source. Natural fibers are broadly categorized into plant-based (cellulosic) and animal-based (protein-based) fibers. Wool is an animal fiber primarily composed of the protein keratin. In contrast, cotton and jute are plant-based fibers consisting mainly of cellulose, which is a polysaccharide polymer. Rubber is a natural polymer derived from the latex of plants like Hevea brasiliensis and is chemically classified as polyisoprene rather than a protein. While DNA and enzymes are also biological polymers made of proteins or polynucleotides within cells, in the context of textile fibers, wool and silk are the primary examples of protein-based polymers. Therefore, among the given options, wool is the only polymer made of protein.

Sources

1. [1] https://www.sciencedirect.com/science/article/abs/pii/S0141813025021889