Download Mutations Worksheet

Mutations Worksheet
Name: __________ANSWER KEY____
Date: ____10-8-08____Block:__2 nd/3rd___
There are three main types of mutations: point missense mutations, point nonsense mutations, and frameshift mutations. In each of
the following DNA sequences, you will use the mRNA and amino acid sequences to identify the mutation that occurred and the effects
of each on, if any. Look and analyze carefully!
Original DNA Sequence:
T A C A C C T T G G C G A C G A C T
mRNA Sequence:
A U G UG G A A C C G C U G C U G A
Amino Acid Sequence:
Methionine – Tryptophan – Asparagine -- Arginine – Cysteine -- STOP
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) A U G U A G A A C C G C U G C U G A
What will be the amino acid sequence? Methionine -- STOP
Will there likely be effects? Yes, the protein will be a Non-functioning, there was only 1 amino acid in it before the STOP CODON.
What kind of mutation is this? NONSENSE, POINT MUTATION
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) A U G C U G G A A C C G C U G C U G A
What will be the amino acid sequence? Methionine – Leucine – Glutamic Acid – Proline – Leucine – Leucine -- ???
Will there likely be effects? Yes, the protein is completely different and didn’t have a STOP codon… so it’s still elongating???
What kind of mutation is this? FRAMESHIFT MUTATION
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) A U G U G G A A U C G C U G C U G A
What will be the amino acid sequence? Methionine – Tryptophan – Asparagine – Arginine – Cysteine -- STOP
Will there likely be effects? NO, because although there was a point mutation it didn’t effect the resulting polypeptide chain.
What kind of mutation is this? MISSENSE, POINT MUTATION
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) A U G U G G A A C C G C U G A U G A
What will be the amino acid sequence? Methionine – Tryptophan – Asparagine – Arginine – STOP
Will there likely be effects? Yes. The protein was truncated (terminated before completion), resulting in a different protein than intended.
What kind of mutation is this? NONSENSE, POINT MUTATION
Mutated DNA Sequence #1:
T A C A C C T T G G G A C G A C T
deletion of G
What will be the corresponding mRNA sequence? A U G U G G A A C C C U G C U G A
What will be the amino acid sequence? Methionine – Tryptophan – Asparagine – Proline – Alanine -- ????
Will there likely be effects? Yes, the protein is completely different and didn’t have a STOP codon… so it’s still elongating???
What kind of mutation is this? FRAMESHIFT MUTATION
1. Which type of mutation is responsible for new variations of a trait? MISSENSE, POINT MUTATION
2. Which type of mutation results in abnormal amino acid sequence? FRAMESHIFT MUTATION
3. Which type of mutation stops the translation of the mRNA? NONSENSE, POINT MUTATION
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