What are the purine and pyrimidine bases?

Nitrogenous bases present in the DNA can be grouped into two categories: purines (Adenine (A) and Guanine (G)), and pyrimidine (Cytosine (C) and Thymine (T)). These nitrogenous bases are attached to C1′ of deoxyribose through a glycosidic bond. Deoxyribose attached to a nitrogenous base is called a nucleoside.

What is the purine pyrimidine rule?

Chargaff’s rules state that DNA from any species of any organism should have a 1:1 stoichiometric ratio of purine and pyrimidine bases (i.e., A+G=T+C) and, more specifically, that the amount of guanine should be equal to cytosine and the amount of adenine should be equal to thymine.

How do purines and pyrimidines work?

Purines and pyrimidines are base pairs. The two most common base pairs are A-T and C-G. These nucleotides are complementary —their shape allows them to bond together with hydrogen bonds. In the C-G pair, the purine (guanine) has three binding sites, and so does the pyrimidine (cytosine).

Why do purines have to pair with a pyrimidine?

Purines pair with pyrimidines because their size and shape make them a perfect fit for hydrogen bonding.

What causes purines to always bond with pyrimidines?

One strand of DNA is always an exact complement of the other as far as purines and pyrimidines go. The reason for this is, purines always bind with pyrimidines, and this is called complementary pairing. Within a DNA molecule the ratio of these two will always be constant.

Are purines and pyramidines in DNA are equal?

Purines and Pyrimidines are two types of nitrogenous bases found as the building blocks of nucleic acid of both DNA and RNA. Equal amounts of purines and Pyrimidines are found in cells.

What are the names of pyrimidines?

The four important pyrimidines include cytosine, thymine, uracil and orotic acid. The difference between DNA and RNA is that DNA contains thymine, whereas RNA has uracil in locations corresponding the thymine’s placement in DNA.