DNA and Gene Mutations
Name:
Objective: To learn the two types of mutations: point mutation and frameshift mutation
To determine which type of mutation is most harmful to an organism
To understand that mutations can be harmful, beneficial, and/or ambivilant
The order of your base pairs on your DNA determines the sequence of amino acids and ultimately your traits. A
mutation is a change that occurs in the DNA sequence. Sometimes, your DNA has an error. This may or may not be
harmful to you. When DNA has an error, the mRNA will copy the error and it may code for a different amino acid.
Sometimes there are errors in translation where a base is added or deleted thus causing the sequence from the error to
shift the codons and thus a whole new group of amino acids are coded for. Sometimes an entire codon is incorrect
and only one amino acid is effected.
Write a hypothesis about which type of mutation will be most harmful to an organism.
Hypothesis: **
Use the following DNA to answer the questions below. Assume you can translate without start codon.
Use the lower strand of DNA for this entire activity.
5’ A T G C A G G T C A T G A T C 3’
| | | | | | | | | | | | | | |
3’ T A C G T C C A G T A C T A G 5’
1.
2.
3.
4.
5.
6.
What do the lines between base pairs represent? **
List the sequence for the DNA Molecule involved in transcription **
List the mRNA sequence. **
List the Codons (groups of three base pairs). **
List the tRNA Anticodons. **
Amino Acid Sequence (Use the codon charts). **
Point Mutation: In a point mutation, a single base pair is matched up with a wrong nitrogenous base.
Scenario. During the championship softball game, you broke your ankle. You are immediately whisked to the
local hospital where an x-ray is taken of your injured ankle. During the x-ray, a mutation occurs to the DNA
strand. The mutation changes ALL of the Guanines to Thymines.
1.
2.
3.
4.
5.
6.
List the sequence for the DNA molecule involved in transcription. **
List the mRNA sequence. **
List the Codons (groups of three base pairs). **
List the tRNA Anticodons. **
Amino Acid Sequence (Use the codon charts). **
How many amino acids are effected by this type of mutation? **
Frame Shift Mutation: In a frame shift mutation, a base pair is added or deleted causing the codons to change
in the entire sequence. In the DNA strand, ALL Guanines are completely deleted.
1.
2.
3.
4.
5.
6.
7.
List the sequence for the DNA Molecule involved in transcription **
List the mRNA sequence. **
List the Codons (groups of three base pairs). **
List the tRNA Anticodons. **
Amino Acid Sequence (Use the codon charts). **
How many base pairs are effected by this type of mutation? **
Which type of mutation causes the most problems in protein synthesis? **