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.