What are nucleotides?
Nucleotides are the building blocks of nucleic acids, they are composed of three subunit molecules - a nitrogenous base, a 5 carbon sugar and a phosphate group.
A nucleoside consists of a nitrogenous base and a 5 carbon sugar. A nucleoside plus a phosphate group yields a nucleotide.
Nucleotides contain a nitrogenous base which maybe either a purine or a pyrimidine.
The 5 carbon sugar is ribose in RNA and deoxyribose in DNA.
Nucleotides are different due to their nitrogen base which may be adenine, cytosine, guanine, thymine (found in DNA only), and uracil (found in RNA only).