BIO 530
Name: _______________________
Unit 6
Date: ________________________
The Central Dogma of Biology
Period: _______________________
Mutations Worksheet
There are three types of mutations that can occur in the DNA sequence:
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Deletions - a base is lost
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Insertions - an extra base is added
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Substitutions - one base is substituted for another
Which of these mutations can cause a frameshift mutation?
Do substitutions always result in a change in the amino acid sequence? Why?
Complete the boxes below. Circle the mutation in both the mRNA and the amino acid
sequence (there is a codon table on the last page). Classify each mutation as a deletion,
insertion, or substitution. (Hint: Watch out for stop codons!)
Original DNA Sequence:
mRNA Sequence:
Amino Acid Sequence:
TAC CCT TAA GGG CAG CCC ACT
Mutation Sequence 1:
TAC CGT TAA GGG CAG CCC ACT
mRNA Sequence:
Amino Acid Sequence:
Mutation Type:
Mutation Sequence 2:
TAC CCT TA GGG CAG CCC ACT
mRNA Sequence:
Amino Acid Sequence:
Mutation Type:
Mutation Sequence 3:
TAC ACT TAA GGG CAG CCC ACT
mRNA Sequence:
Amino Acid Sequence:
Mutation Type:
Mutation Sequence 4:
TAC CCT TAA GGT CAG CCC ACT
mRNA Sequence:
Amino Acid Sequence:
Mutation Type:
Mutation Sequence 5:
mRNA Sequence:
Amino Acid Sequence:
Mutation Type:
TAC CCT TAA GGG CAG CCA ACT
1. Which location in the codon (first, second or third base) is least likely to cause a
mutation? (Hint: you may want to take a look at your codon table to help with this one)
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2. Which type of mutation do you think is most serious?
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Extra Credit: Sickle Cell Anemia
Sickle cell anemia is the result of a type of mutation in the gene that codes for part of the
hemoglobin molecule. Hemoglobin carries oxygen in your red blood cells. The mutation causes
these red blood cells to become stiff & sickle-shaped when they release their oxygen. The sickled
cells tend to get stuck in blood vessels, causing pain and increased risk of stroke, blindness, damage
to the heart & lungs, and other conditions.
Analyze the DNA strands below to determine what amino acid is changed AND what type of
mutation occurred
Normal hemoglobin DNA
C A C G T A G A C T G A G G A C T C
Normal hemoglobin mRNA
Normal hemoglobin AA sequence
---------------------------------------------------------------------------------------------------------------Sickle cell hemoglobin DNA
Sickle cell hemoglobin mRNA
Sickle cell hemoglobin AA sequence
What type of mutation is this?
C A C G T A G A C T G A G G A C A C