Which term describes long chains such as proteins, nucleic acids, and carbohydrates that are large in size?

• A. Polymers
• B. Carbohydrates
• C. Proteins
• D. Lipids

Answer: (A)

A polymer is a large molecule made up of many repeating subunits. This fits proteins, nucleic acids, and polysaccharides because each is built by linking together numerous smaller units—amino acids, nucleotides, and sugar units, respectively. The bonds that join these units—peptide bonds in proteins, phosphodiester bonds in nucleic acids, and glycosidic bonds in polysaccharides—create long, chain-like structures with diverse functions. Lipids don’t form long repeating chains from monomers in the same way, so they aren’t polymers in the same sense. That makes polymer the best term for describing these large, chain-like molecules.