Structure of DNA

Rosalind Franklin and Maurice Wilkins used x-ray diffraction to capture the famous Photo 51, which provided critical data about the helical structure of DNA.

According to Chargaff's rules, Adenine equals Thymine (15% each, total 30%). The remaining 70% is split equally between Cytosine and Guanine (35% each).

The two strands of the DNA double helix are held together by hydrogen bonds between the complementary nitrogenous bases.

A nucleotide consists of three components: a phosphate group, a 5-carbon sugar (deoxyribose or ribose), and a nitrogenous base.

Erwin Chargaff discovered that the amount of adenine equals thymine and the amount of guanine equals cytosine, which provided the basis for base-pairing rules.

In DNA, G pairs with C and T pairs with A. GGTCTAAC becomes CCAGATTG.

Purines are double-ring nitrogenous bases, which include adenine and guanine. Pyrimidines are single-ring bases, which include cytosine and thymine.

DNA stands for deoxyribonucleic acid, which contains the 5-carbon sugar deoxyribose.

Nucleotides are the basic structural units (monomers) that link together to form DNA and RNA polymers.

James Watson and Francis Crick are credited with building the first correct 3-D model of the DNA double helix in 1953.