Describe the structural differences between DNA and RNA.

DNA is a double stranded macromolecule which is composed of nucleotides . The two DNA stands, joined by hydrogen bonds between the nucleotides and running antiparrallel to each other form a double helix structure. RNA is a single stranded and a relatively short polynucleotide. The nucleotides can have one of four nitrogenous bases, in DNA the bases are Adenine (A),Thymine (T), Cytosine (C) and Guanine (G). RNA contains the same bases except that it does not contain Thymine, instead it contains Uracil (U). These bases are complementary to each other and can form hydrogen bonds with the other corresponding completmentary base. Cytosine is complementary to Guanine whilst Adenine is complementary to Thymine (in DNA) and Uracil (in RNA). The nucleotide is also composed of phosphate group which is attached to a pentose sugar. The type of pentose sugar is different between DNA and RNA. In DNA  the pentose suger is Deoxyribose whilst in RNA the pentose suger is ribose.