3Definition: A mutation is… A change in the arrangement of bases in an individual gene or in the structure of the chromosome (which changes the arrangement of genes).
4Frequency and repair of mutations Mutations can occur in gametes and somatic cells.Chance of mutation is between 2-30 x 10-7Faulty DNA can be repaired by specific enzymes.Unrepaired mutations will affect the new proteins being synthesised
5Point mutations are caused by: Changes in an individual gene due to miscopying of one or more nucleotides.Deletion or insertion of a nucleotide results in a frameshift:C A T G C GAT C A G A TCodon 1Codon 2Codon 3Codon 4ValTyrArgAlaSerLeu
6Point mutations T A C G T G A A A T C G G C A T Met His Phe Leu Ala Substitution mutations result in a change of one base:T A C G T G A AATC G G C A TMetHisPheLeuAlaVal
8Chromosome mutations B A C D E B A C D E W X Z Y Inversion: Translocation:BACDEWXZY
9Whole-chromosome mutations An entire chromosome is lost or repeated during cell division.Example: Downs syndrome is caused by having an extra chromosme 21.
10The effect of mutations Production of new/superior protein: Results: gain of reproductive advantageNeutral mutation: Result: No changeProduction of inferior or no protein: Result: Fatal and/or disease causing.
11Causes of mutationsMutagens such as: X-rays ionising radiation chemicals
12Summary Define the term: translocation somatic duplication deletion mutationinsertioninversionDown’s syndromemutagen