20.1 Flashcards
6 Mutations
- substitution of bases
- deletion of bases
- addition of bases
- duplication of bases
- inversion of bases
- translocation of bases
Mutation
change to the base sequence of DNA
Base substitution
- Base sequence is changed
- Triplet now codes for different amino acid
- Changes primary structure of protein
- Changes tertiary structure as different bonds form
-Active site is changed(no longer complementary)
Degenerate code
-Base triplet codes for same amino acid
-Primary sequence isn’t changed
-Tertiary shape is the same
-Polypeptide is functional, mutation has no affect
Base sub of stop codon
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-Formation of stop codon stops production of polypeptide prematurely
-Primary sequence is changed
- Final protein non-functional and very different
Deletion of bases
-Base sequence is changed as base is removed
- Frame shift to the left occurs
-Triplet bases are completely different and code for completely different amino acids
-Primary sequence is completely different
-Tertiary sequence changes
-Protein is non-functional
Addition of bases
-Base sequence is changed as base is added
- Frame shift to the right occurs
-Triplet bases are completely different and code for completely different amino acids
-Primary sequence is completely different
-Tertiary sequence changes
-Protein is non-functional
Addition of 3 bases
- no frame shift
- codes for extra amino acid
- primary sequence changed
-tertiary sequence changed
duplication of bases
- one or more bases repeated
- frame shift to the right
Inversion of bases
- group of bases separate from DNA sequence
-rejoin in inverse order
translocation of bases
- group of bases separate from DNA sequence on one chromosome
- insert into DNA sequence on different chromosome
Mutagenic agents
- high energy ionising radiation
- chemicals(e.g. nitrogen dioxide)
Genome
entire genetic material of an organisms in the nucleus of a cell
