There is part of an amino acid molecule that is called the R group or side chain. The side chain of the amino acid called glycine is a single hydrogen atom. The side chain is what differs from amino acid to amino acid.
Answer : A nucleotide is composed of a phosphate group and a nitrogen-containing base.
Explanation :
Nucleotide : It is a building block of nucleic acids or we can say that it is building block of DNA and RNA.
It is composed of three sub-unit molecules which are a nitrogenous base, a five-carbon sugar and one phosphate group.
Nucleotide forms covalent bonds with other nucleotide for the formation of the nucleic acid strand.
Hence, a nucleotide is composed of a phosphate group and a nitrogen-containing base.