- Created by: Ellsbells98
- Created on: 04-06-15 19:54
DNA - a double helix of based pairs
A DNA molecule has two strands coiled together in the shape of a double helix (two spirals).
The two strands are held together by chemicals called bases. There are four different bases - Adenine (A), Cytosine (C), Guanine (G), Thymine (T).
The bases are paired, and they always pair up in the same way, it's always A-T, and C-G. This is called base pairing.
The base pairs are joined together by weak hydrogen bonds.
A gene is a section of DNA, and the sequence of bases in a gene code for a specific protein.
Rosalind Franklin and Maurice Wilkins worked out that DNA had a helical structure by directing beams of x-rays onto crystallised DNA and looking at patterns the x-rays formed as they bounced off.
James Watson and Francis Crick used…