Alleles

STRUCTURE OF DNA.
The structure of DNA was first explained in 1953 by Watson and Crick.
DNA was shown to be a double helix that coils around itself.
The two strands are parallel and the distance between the two is constant.

Components of DNA

DNA is made up of repeating units called nucleotides.
Each nucleotide is composed of:
A five-carbon sugar (deoxyribose).