List of top Chemistry Questions on Structure of DNA and RNA asked in Common University Entrance Test

Which of the following is/are the bases of DNA?
(A) Adenine
(B) Uracil
(C) Thymine
(D) Cytosine

James Watson and Francis Crick gave a double strand helix structure for DNA. Two Nucleic acid chains are wound about each other and held together by hydrogen bonds between pairs of bases. The two strands are complementary to each other because the hydrogen bonds are formed between specific pairs of bases. Adenine forms hydrogen bonds with thymine whereas cytaine forms hydrogen bonds with quanine.

The presence or absence of hydroxyl group on which carbon atom of sugar differentiate RNA and DNA: