Mutations Practice Worksheet:
Name:_____________________________
Period___
There are two main types of Mutations:
Chromosomal mutations, where parts of the chromosome are changed
Gene Mutations, (Point mutations) where bases within the gene segment are changed, at one point
There are 3 kinds of gene mutations: Substitution, Insertion or deletion
Substitution: Where one base pair is replaced by another ex: G to C, A to T or any combination of this
Insertion: Where more bases are added to a sequence ex: ACTAGCC to ACCTAGCC
Deletion: Where bases are removed from a sequence ex: ACTAGCC to ATAGCC
The above mutations lead to various effects or results:
Silent Mutation= when a base pair is substituted but the change still codes for the same amino acid in the sequence
Substitution Mutation= when a base pair is substituted and the change codes for a new amino acid in the sequence.
Missense Mutation= when a substitution results in the formation of a STOP codon before the whole sequence can be
read.
Frameshift Mutation= when a deletion or insertion results in a different base pair being at the beginning of the next
codon, changing the whole sequence of amino acids after that point.
Codon Deletion or Insertion= when a whole codon of bases are inserted or deleted and then a new amino acid is added
or deleted.
Using the genetic codon chart below, please write out the mRNA sequence and amino acid sequence for the original
DNA strand and then compare the mutated strands to the original to determine the change and effect of the mutation.