Name: Date: Period:
Mutations Practice Worksheet
1. Define the following words:
Mutation
Gene
2. The basic 3 types of gene mutations are:
3. Transcribe the following “normal” DNA sequence into mRNA. Then use your codon chart to translate the
mRNA into amino acids. The normal DNA sequence represents a normal gene. Remember that a gene is a
sequence of DNA that codes for a particular protein.
Normal DNA Gene Sequence DNA T – A – C – G – C – T – T – C – G – A – A – G – C – T – C – A – A – C – G – G – C – A – C - T
mRNA
Amino
Acids
4. Mutation #1: Compare the mutated strand of DNA in the table below to the normal strand of DNA. What
difference do you notice?
Normal
DNA
T – A – C – G – C – T – T – C – G – A – A – G – C – T – C – A – A – C – G – G – C – A – C - T
Mutated
DNA
T – A – C – G – C – A – T – C – G – A – A – G – C – T – C – A – A – C – G – G – C – A – C –T
mRNA
Amino
Acids
1. This is an example of a __________________ mutation.
2. Base #_______ which was a _____ was substituted for a _____.
3. How many Amino Acids were changed by this mutation? _____
4. Did this mutation change the gene and therefore the overall protein that would be produced? Explain
why or why not.
SUBSTITUTION INSERTION DELETION
A CHANGE IN THE NUCLEOTIDE SEQUENCE IN THE GENETIC CODE FOR A PROTEIN
A NUCLEOTIDE SEQUENCE IN THE DNA THAT CODES FOR A TRAIT
A U G C G A A G C U U C G A G U U G C C G U G A
MET ARG SER PHE GLU LEU PRO STOP
T WAS REPLACED BY A IN THE MUTATED SEQUENCE OF THE SECOND CODON
A U G C G U A G C U U C G A G U U G C C G U G A
MET ARG SER PHE GLU LEU PRO STOP
POINT/SUBSTITUTION/SILENT
6 T A
NONE
NO. IT WAS A SILENT MUTATION. EVEN THOUGH A BASE WAS SUBSTITUTED FOR ANOTHER
THE AMINO ACID FROM THAT MUTATION DID NOT CHANGE, NOT AFFECTING THE PROTEIN
5. Mutation #2: Compare the mutated strand of DNA in the table below to the normal strand of DNA. What
difference do you notice?
Normal
DNA
T – A – C – G – C – T – T – C – G – A – A – G – C – T – C – A – A – C – G – G – C – A – C - T
Mutated
DNA
T – A – C – G – C – T – T – C – G – A – A – A – G – C – T – C – A – A – C – G – G – C – A – C - T
mRNA
Amino
Acids
1. This is an example of a(n) __________________ mutation (be specific)
2. A(n) _____ was inserted at position # _____.
3. How many Amino Acids were changed? _____
4. How did this mutation change the gene? Explain.
6. Mutation #3: Compare the mutated strand of DNA in the table below to the normal strand of DNA. What
difference do you notice?
Normal
DNA
T – A – C – G – C – T – T – C – G – A – A – G – C – T – C – A – A – C – G – G – C – A – C - T
Mutated
DNA
T – A – G – C – T – T – C – G – A – A – G – C – T – C – A – A – C – G – G – C – A – C – T
mRNA
Amino
Acids
1. This is an example of a(n) __________________ mutation (be specific)
2. A(n) _____ was deleted at position # _____
3. How many Amino Acids were changed? _____
4. How did this mutation change the gene? Explain.
Conclusion
What type of mutation has the least chance of changing a gene? _______________
Which types of mutations have the best chance of changing a gene? ________________ and ______________
In this activity, which mutation caused the most damage? Explain.
A U G C G A A G C U U U C G A G U U G C C G U G A
AN "A" BASE WAS INSERTED IN THE FOURTH CODON.
MET ARG SER PHE ARG VAL ALA VAL ---
INSERTION
A 12
4
AN INSERTION CHANGED EVERY AMINO ACIDAFTER THE INSERTION POINT.
A U C G A A G C A U C G A G U U G C C G U G A
LLE GLU ALA SER SER CYS ARG -------
THE THIRD LETTER "C" IN ORIGINAL DNA WAS DELTED
DELETION
C 3
8
IT COMPLETELY CHANGED THE GENETIC CODE FOR A PROTEIN.
POINT MUTATION
INSERTION DELETION
FRAMESHIFT. ONCE AN INSERTION/DELETION HAPPEN, THE ENTIRE AMINO ACID SEQUENCE AFTER THAT IS AFFECTED.