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Molecular Basis of Inheritance — BIOLOGY STD 12 Science — Question

Bihar BoardEnglish MediumSTD 12 ScienceBIOLOGYMolecular Basis of Inheritance3 Marks
Question
What is mutation? Explain with the help of an example how does a point mutation affect the genetic code. Name another type of mutation.
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Answer

A mutation is a stable, inheritable change in genetic material. A classical example of point mutation is a change of single base pair in the gene for B-globin chain that results in the change of amino acid residue glutamate to valine. It results into a diseased condition called Sickle-cell anaemia.
The insertion or deletion of one or two bases may change the reading frame from the point of insertion or deletion Insertion or deletion of three or its multiple bases insert or delete one or multiple codon, hence one or multiple amino acid may be formed in polypeptide. The other type of mutation is frameshift insertion or deletion mutation.

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