Unit 9 – Protein Synthesis DNA MUTATIONS

W HAT ARE MUTATIONS ?  Mutations are changes in genetic material (DNA)  Happens when cells make mistakes copying their own DNA  DNA can be deleted  Bases can be skipped  Bases can be exchanged

T YPES OF M UTATIONS  Chromosome mutations  Changes that happen in whole chromosomes  Gene mutations  Changes that happen in a single gene

T YPES OF G ENE M UTATIONS  Point Mutations  Changes in one or a few nucleotides

T YPES OF P OINT MUTATIONS  Insertion  Original – ATCGC  Mutation – ATCCGC  Substitution  Original – ATCGC  Mutation – ATCGT  Usually affect only a single AA

M ORE P OINT M UTATIONS  Deletions  Original – ATCTGT  Mutation - ATTGT

F RAMESHIFT M UTATION a) We call Insertions and Deletions FRAMESHIFT MUTATIONS because they change the way we read the codons. This means that we will code for entirely different AA’s and this entirely wrong proteins.

C HROMOSOME M UTATIONS  Involves changes in the number or structure of chromosomes  May change the location of genes on chromosomes and even the number of copies of a gene

F OUR T YPES OF C HROMOSOME MUTATIONS

W HY ARE MUTATIONS BAD ??  Most mutations are neutral meaning they have no effect on the proteins being made  However, those that do cause changes in protein structure or function can be extremely harmful to humans.  Disruption of normal biological activity

W HY ARE MUTATIONS BAD ??  Mutations can be a source of genetic variability and are therefore not always bad for us.  Other more harmful mutations such as chromosome mutations can cause many genetic disorders which we will be learning about in the next chapter.

D ISEASES CAUSED BY MUTATIONS  Cri du Chat  Deletion  Sickle Cell Anemia  Point Mutation  Down Syndrome  Extra #21 chromosome