2 Protein synthesis summary DNAACTGCGAUmRNAtranscriptionnucleusGlySerPheTrpPROTEINtranslationCytoplasm:ribosome
3 Definition: 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).
4 Frequency 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
5 Point 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
6 Point 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
8 Chromosome mutations B A C D E B A C D E W X Z Y Inversion: Translocation:BACDEWXZY
9 Whole-chromosome mutations An entire chromosome is lost or repeated during cell division.Example: Downs syndrome is caused by having an extra chromosme 21.
10 The 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.
11 Causes of mutationsMutagens such as: X-rays ionising radiation chemicals