Mutations Flashcards
what do gene mutations involve
a change in the DNA base sequence of chromosomes
what are the types of errors than can occur in mutation
substitution and deletion
what occurs in substitution
one base is substituted with another, e.g. ATGCCT becomes ATTCCT (G is swapped for T).
what occurs in deletion
one base is deleted, e.g. ATGCCT becomes ATCCT (G is deleted)
what does the order of DNA bases in a gene determine
the order of amino acids in a particular protein, if a mutation occurs in a gene, the sequemce of amino acids it codes for and the protein formed could be altered
what does the degenerate nature of the genetic code mean
that some amino acids are coded for by more than one DNA triplet e.g. tyrosine can be coded for by TAT or TAC in DNA. This means that not all substitution mutations will result in a change to the amino acid sequence of the protein- some substitutions will still code for the same amino acid
substitution mutations wont always lead to changes in the amino acid sequence, but deletions will, what will the deletion of a base change
the deletion of a base will change the number of bases present which will cause a shift in all the base triplets after it
what can deletion do that substitution cannot always do
lead to changes in the amino acid sequence
when do mutations occur
spontaneously e.g. when DNA is misread during replication
what are mutagenic agents
things that can cause an increase in the rate in mutations e.g. ultraviolet radiation, ionising radiation, some chemicals and some viruses
what is the name of things than can increase mutation rate
mutagenic agents
