Definition :
DNA is a senetic material (heritable material) responsible for inheritance.
Introduction :
Chromosomes are made up of basic proteins and nucleic acids. Nucleic acids discovered by Friedrich Miescher in 1869 ( from nuclei of pus cells) DNA is found in the nucleus as well as cytoplasm. It is the storehouse of genetic material. DNA is composed of Nucleotides. (Here, the two nucleotides linked through 3’-5’ phosphodiester linkage). These nucleotides called ‘deoxyribosenucleotides’ (composed of deoxyribose sugar + nitrogenous base + phosphoric acid).
Fig : Moleculer Structure DAN + RNA
Sub-title : 1
(A) Ribose Sugar – In DNA, deoxyribose type of sugar is present as compared to RNA, where ribose sugar is present.
( It is due to the presence of bulky hydroxyl (OH) group at (-2, position of ribose sugar of RNA. This (-OH) group makes RNA move susceptible to chemicals and enzymatic degradation and making RNA molecule less stable)
(B) Nitrogenous Bases – (Two types) :
(i) Purines – Adenine (A) and Guanine (G) constitutes (dicyclic) purines.
Fig : Adenine & Guanine
(ii) Pyrimidines – Common pyrimidines (monocyclic) in DNA are Thymine (T) and Cytosine (C ) While, in RNA instead of Thymine(T), Uracil (U) is present.
Figure: