Structure of DNA (short note) (352)

Structure of DNA:

DNA is a very complex molecule. It contains many units, which are arranged in a chain, these units are called nucleotides. Each nucleotide consists of three compounds.

1. Deoxyribose sugar 
2. Phosphoric Acid
3. Organic base (Nitrogen bases)

These are four different types of organic bases found in DNA molecule. Hence there are four different types of nucleotides. They are Adenine, Thymine, Cytosine and Guanine. Millions of these nucleotides combune to form a single molecule of DNA. The close study of Nucleotides reveals that adenine and guanine bases have double ring structure, called purine bases and an other hand, cytosine and thymine base have single ring structure, called pyrimidine bases. 

        These nucleotides are joined with one another through phosphoric acid in such a way that the C^3 position of one deoxyribose is linked to the C^5 position of the next.