Download Modeling Mutations Activity

Name: _____________________________________ Block: ____________ Date: _______________
Activity: Modeling Gene Mutations
1. What is a mutation? _________________________________________________________________
_______________________________________________________________________________________
Part A. Transcription and Translation
Consider the following strand of DNA:
G A C T G C A C G T C G A T C T
2. Transcribe this strand forming the appropriate mRNA strand:
3. Mark off the codons. How many are there? _________________
4. Using a codon chart, translate the mRNA code into the amino acids that form the
polypeptide chain (protein).
Polypeptide:
Part B. Point Mutations
5. What is a point mutation? ___________________________________________________________
_______________________________________________________________________________________
Modeling a point mutation: Using the DNA strand in Part A, model a point mutation by
changing the third nucleotide base from cytosine to adenine leaving all the other
nucleotide bases the same.
6. Write the sequence of bases for the mutated DNA strand:
7. Transcribe the mRNA strand and mark off the codons:
8. Translate the code into a polypeptide chain:
9. How has the point mutation changed the polypeptide chain from the original
polypeptide chain? ___________________________________________________________________
_______________________________________________________________________________________
10. How does this show evidence that not all mutations are harmful? ____________________
_______________________________________________________________________________________
_______________________________________________________________________________________
Part C. Frameshift Mutations
11. What is a frameshift mutation? ______________________________________________________
_______________________________________________________________________________________
Modeling frameshift mutations: Using the DNA strand in Part A, model a frameshift mutation
by deleting the third nucleotide base (C). Leave all other nucleotides the same.
12. Write the sequence of bases for the mutated DNA strand:
13. Transcribe the mRNA molecule and mark off the codons:
14. Translate the code into a polypeptide chain:
15. How has the frameshift mutation changed the polypeptide chain? ___________________
_______________________________________________________________________________________
_______________________________________________________________________________________
16. Why can a frameshift mutation be considered more serious than a point mutation?
Why could this be harmful to a cell?
_______________________________________________________________________________________
_______________________________________________________________________________________
_______________________________________________________________________________________