Molecular Basis of Inheritance Question 107
107. Out of A-T, G-C pairing, bases of DNA may exist in alternate valency state owing to arrangement called
(a) analogue substitution
(b) tautomerisational mutation
(c) frame-shift mutation
(d) point mutation
Show Answer
Answer : b
Hints & Solution
(b) The tautomer forms of nitrogen bases are imino-tautomer instead of amino group (e.g. cytosine, adenine) or enol instead of the keto group (e.g. thymine, guanine). Tautomers are organic compounds that are interconvertible by a chemical reaction called tautomerisation. The concept of tautomers that are interconvertible by tautomerisations is called tautomerism. Tautomerism is a special case of structural isomerism and can play an important role in non-canonical base pairing in DNA and especially RNA molecules.
