Which term best describes the polymeric subunits of DNA and RNA?

Which term best describes the polymeric subunits of DNA and RNA?

• A. Amino acid
• B. Nucleoside
• C. Nucleotide
• D. Monomer

Answer: (C)

Nucleotides are the repeating subunits that make up DNA and RNA. Each nucleotide contains a sugar (deoxyribose in DNA or ribose in RNA), a phosphate group, and a nitrogenous base. The nucleotides link together through phosphodiester bonds between the phosphate of one nucleotide and the sugar of the next, forming the sugar–phosphate backbone of the polymer and encasing the genetic information in the sequence of bases. Amino acids are the building blocks of proteins, not nucleic acids. A nucleoside is a sugar bound to a base but lacks the phosphate group, so it is not the polymer unit of DNA or RNA. A monomer is a general term for any single repeating unit in a polymer, but the specific monomer for nucleic acids is a nucleotide, which is why it’s the best description here.

Nucleotides are the repeating subunits that make up DNA and RNA. Each nucleotide contains a sugar (deoxyribose in DNA or ribose in RNA), a phosphate group, and a nitrogenous base. The nucleotides link together through phosphodiester bonds between the phosphate of one nucleotide and the sugar of the next, forming the sugar–phosphate backbone of the polymer and encasing the genetic information in the sequence of bases.

Amino acids are the building blocks of proteins, not nucleic acids. A nucleoside is a sugar bound to a base but lacks the phosphate group, so it is not the polymer unit of DNA or RNA. A monomer is a general term for any single repeating unit in a polymer, but the specific monomer for nucleic acids is a nucleotide, which is why it’s the best description here.