mutations Flashcards
what is a mutation
change in DNA base sequence
what are the three types of mutations
substitution, insertion and deletion
what are point mutations
affect only 1 nucleotide
what is substitution
when a base has been replaced by another base
what is insertion
an extra base is added
what is deletion
a base is removed
what do insertion and deletion lead to
frameshift mutation
what is a frameshift mutation
disrupts triplet code reading (codon)
what is a codon
a sequence of three bases which codes for a particular amino acid
how is the genetic code degenerate
multiple codons can code for one particular amino acid, meaning a point mutation may have no affect
what is a silent mutation
when the change to a base sequence still codes for the same amino acid
what is a missense mutation
a change in the case sequence which codes for a different amino acid
what is a nonsense mutation
when a codon has changed into a stop codon, premature end (shorter than expected)
what are the effects of mutations
neutral
beneficial
harmful
what is a neutral effect
no effect (degenerate)
