Final answer:
DNA and RNA are nucleic acids made up of nucleotide monomers. DNA has a double helix structure, while RNA is single-stranded.
Step-by-step explanation:
DNA and RNA are nucleic acids that are made up of monomers called nucleotides. Each nucleotide consists of three components: a nitrogenous base, a pentose (five-carbon) sugar, and a phosphate group. In DNA, the nitrogenous bases are adenine (A), guanine (G), cytosine (C), and thymine (T). In RNA, uracil (U) replaces thymine.
The DNA molecule is a double helix, with the two strands held together by hydrogen bonds between the paired nitrogenous bases. The sugar-phosphate backbones of the two strands run in opposite directions, creating a characteristic 'twisted ladder' structure. In RNA, the structure is single-stranded.