Nitrogenous base

 Nitrogenous bases are found in nucleotides. There are four different nucleotides in DNA; Adenine (A), Cytosine (C), Guanine (G) andThymine (T) [1]. There is also a base called Uracil however this only occurs in RNA. These are then grouped as either aPurine (A and G) or a Pyrimidine (C and T in DNA and U in RNA). A Purine always pairs with a pyrimidine.Purines are also bigger in size that pyrimidines.Nitrogenous bases are the key to base pairing; A will always bind with T in DNA unless in RNA where A will bind with U. G and C will always bind together regarless whether it is DNA or RNA [1]. The nitrogenous base is one of the three components of of a nucleotide which in turn join up to form DNA. The three components of a nucleotide are a phosphate group, a pentose sugar and a nirtogenous base [2].

Refrences

[1] Alberts, BA,Johnson, AJ,Lewis, JL, Raff,MR, Roberts, KR, Walters, PW. 2008. The Cell. Fifth Edition. 197-198.

[2] Alberts, BA,Johnson, AJ,Lewis, JL, Raff,MR, Roberts, KR, Walters, PW. 2008. The Cell. Fifth Edition.116-117.