Describe the structure of DNA (6 marks)
DNA has a double helix structure made up of two strands twisted together.
DNA is made up of 4 bases: adenine (A) , cytosine (C) , guanine (G) and thymine (T).
A and T are complimentary base pairs as well as C and G.
Between the bases there are weak hydrogen bonds.
C and G particularly have 3 hydrogen bonds and A and T have 2 hydrogen bonds.
DNA is a polymer because it is made up of many repeating nucleotides.
A nucleotide is made up of a base attached to deoxyribose sugar attached to a phosphate group.
