Gene Mutation (AQA A-Level Biology): Flashcards
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Mutation (definition)
Mutation (definition)
Any change in the quantity or base sequence of DNA in an organism
Gene mutation (definition)
Gene mutation (definition)
Changes to one or more nucleotide bases within a gene
Substitution mutation
Substitution mutation
Occurs when one nucleotide is replaced by another with a different base
Deletion mutation
Deletion mutation
Occurs when a nucleotide is lost from the normal DNA sequence
Reading frame shift (cause)
Reading frame shift (cause)
Deletion shifts all subsequent triplets by one position
Why deletion mutations more severe
Why deletion mutations more severe
Affect entire protein downstream from mutation site
Degenerate genetic code (meaning)
Degenerate genetic code (meaning)
Most amino acids coded by more than one DNA triplet
Polyploidy (definition)
Polyploidy (definition)
Possessing three or more complete sets of chromosomes
Non-disjunction (definition)
Non-disjunction (definition)
Failure of homologous pairs to separate in meiosis
Down's syndrome chromosome count
Down's syndrome chromosome count
47 chromosomes (extra chromosome 21)