VCE MUTATIONS WORKSHEET
There are several types of mutation:
DELETION (a base is lost)
INSERTION (an extra base is inserted)
Deletion and insertion may cause what’s called a FRAMESHIFT, meaning the reading
“frame” changes, changing the amino acid sequence.
POINT MUTATION (one base is substituted for another)
If a point mutation changes the amino acid, it’s called a MISSENSE mutation.
If a point mutation does not change the amino acid, it’s called a SILENT mutation.
If a point mutation changes the amino acid to a “stop,” it’s called a NONSENSE mutation.
Complete the boxes below. Classify each as either Deletion, Insertion, or Substitution AND as either
frameshift, missense, silent or nonsense (hint: deletion or insertion will always be frameshift).
Original DNA Sequence: A C A C C T T G G C G A C G A C T
mRNA Sequence:
_____________________________________
Amino Acid Sequence: _____________________________________
Mutated DNA Sequence #1: T A C A T C T T G G C G A C G A C T
What’s the mRNA sequence? _____________________________________(Circle the change)
What will be the amino acid sequence? _____________________________________
Will there likely be effects?
_______________________________________
What kind of mutation is this? ____________________________________________
Mutated DNA Sequence #2: T A C G A C C T T G G C G A C G A C T
What’s the mRNA sequence? _____________________________________(Circle the change)
What will be the amino acid sequence? _____________________________________
Will there likely be effects?
_______________________________________
What kind of mutation is this? ____________________________________________
Mutated DNA Sequence #3: T A C A C C T T A G C G A C G A C T
What’s the mRNA sequence? ___________________________________(Circle the change)
What will be the amino acid sequence? _________________________________
Will there likely be effects? _________________________________________
What kind of mutation is this? ________________________________________
Mutated DNA Sequence #4: T A C A C C T T G G C G A C T A C T
What’s the mRNA sequence? ____________________________________________ (Circle the
change)
What will be the amino acid sequence? _____________________________________
Will there likely be effects? ______________________________________________
What kind of mutation is this? ________________________________________
Original DNA Sequence:
TACACCTTGGCGACGACT
mRNA sequence: _________________________________________________
Amino acid sequence: ______________________________________________
Mutated DNA Sequence #5: TACACCTTGGGACGACT
What’s the mRNA sequence _________________________________ (Circle the change) What
will be the amino acid sequence? ________________________________
Will there likely be effects? ____________________________________
What kind of mutation is this? __________________________________
1.
Which type of mutation can cause new variations of a protein?
2.
Which type of mutation results in abnormal amino acid sequence?
3.
Which type of mutation stops the translation of the mRNA?
Review Questions
1. A geneticist found that a particular mutation had no effect on the protein coded for by the gene
What do you think the is the most likely type of mutation in this gene? Why?
2. Name one amino acid that has more than one codon. Name one amino acid that has only one
codon.
3. Look at the following sequence: THE FAT CAT ATE THE RAT. Delete the first “H” and regroup
the letters in groups of three. Write out the new groups of three. Does the sentence still make sense?
What type of mutation is this an example of?
4. Two of the following three RNA sequences code for the same protein – which two?
#1 AGU UUA GCA ACG AGA UCA
#2 UCG CUA GCG ACC AGU UCA
#3 AGC CUC GCC ACU CGU AGU
How many point mutations are there between the two sequences?
5. You have an RNA transcript that is 105 nucleotides long. How many amino acids will be in the
resultant protein?
6. You have an RNA transcript that is 105 nucleotides long. A frameshift mutation occurs at the 85th
nucleotide. How many amino acids will be correct?