gene mutation Flashcards
define mutation
change in quantity or structure of DNA in an organism
define gene mutation
change or rearrangement of nucleotide bases in DNA
what are the 6 types of gene mutation
base substitution
base addition
base inversion
base deletion
base duplication
base translocation
what 3 types of gene mutation can be described as frame shift
- base addition
- base deletion
- base duplication
what can be the 3 effects of a base subsitution
- stop codon is formed and the polypeptide is not complete
- codon for a different amino acid is formed
- codon for the same amino acid is formed
what are the effects of a base addition
- frame shift to the right
- alters whole sequence of amino acids
primary, secondary, tertiary structure of protein changed
structure and function of a protein changed
high chance of changing phenotype
what are the effects of a base inversion
- affects amino acid sequence at this part but not before or after
- codon different = different amino acid
- codon same = same amino acid
- stop codon
what are the effects of a base deletion
- frame shift to the left
- alters whole sequence of amino acids
- primary, secondary, tertiary structure changed
- change in function and shape
HIGH chance of changing phenotype
what are the effects of a base duplication
- frame shift to the right
- alters whole sequence of amino acids
different primary, secondary, tertiary structure - different shape and function
HIGH chance of changing phenotype
what is the mechanism for a base translocation
sequence of bases separated from DNA on one chromosome and added to DNA of a different chromosome
what are the effects of a base translocation
significant effect on gene expression leading to abnormal phenotype
describe 3 causes of mutation (3 marks)
- arise spontaneously during DNA replication
- high energy ionising radiation
- chemicals
