EXPLAIN Mutations Name:_______________
Term Definition
Mutation
Gene mutation
Mutagen
Chromosome
mutation
Somatic
mutation
Germ line
mutation
Read the information on Gene Mutations and answer the questions.
Type of Gene Description of Mutation Effect/s on amino acid sequence
(Point) Mutation
Substitution
Silent
substitution
Insertion
Deletion
mRNA Codon and corresponding amino acid table
Normal Gene
Non- mutated DNA AAA ATG TTT CTC CAA GAT
mRNA UUU UAC AAA GAG GUU CUA
Amino acid sequence coded for
Gene Mutation Problem 1: Substitution
In the following DNA sequence replace the G of the second codon with an A to create a new mutant DNA.
Determine the new mRNA sequence and the amino acid sequence.
Mutant DNA AAA ATA TTT CTC CAA GAT
mRNA UUU UAU AAA GAG GUU CUA
Amino acid sequence coded for
a) Describe the effect of the substitution mutation on the amino acid sequence of the protein
Gene Mutation Problem 2: Deletion
In the following DNA sequence, a mutation of the same gene from the last example, a deletion mutation has
occurred. Refer to the “normal gene” on the previous page.
Mutant DNA AAA ATA TTC TCC AAG ATA
mRNA UUU UAU AAG AGG UUC UAU
Amino acid sequence coded for
b) Annotate (draw an arrow) showing the location of the deletion mutation.
c) Describe the effect on the amino acid sequence.
Gene Mutation Problem 3: Determine the type and effect
In the following DNA sequence, a mutation of the same gene from the last example has occurred. Refer to the
“normal gene” on the previous page.
Mutant DNA AAA ATG TTT ACT CCA AGA
mRNA UUU UAC AAA UGA GGU UCU
Amino acid sequence coded for
d) Annotate (draw an arrow) showing the location of the mutation.
e) Name this type of mutation.
f) Describe the effect of this mutation.
g) Is this mutation likely to change the protein coded for in this gene? Explain why/why not.
EXPLAIN Mutations Name:_______________
Term Definition
Mutation A permanent change in the sequence of bases in the DNA
Gene mutation A permanent change in the sequence of bases in the DNA that code
for a protein.
Mutagen Anything that causes a mutation, e.g.: radiation, chemicals, viruses
Chromosome A mutation that affects the whole chromosome or a large part of it.
mutation
Somatic A mutation that occurs in a body cell.
mutation
Germ line A mutation that occurs in the sex cells
mutation
Read the information on Gene Mutations and answer the questions.
Type of Gene Description of Mutation Effect/s on amino acid sequence in protein
(Point) Mutation being coded for
Substitution One base replaces another in May change one amino acid in a protein.
the sequence
Silent One base replaces another in the None
sequence with no change in the
substitution sequence of amino acids.
Insertion An extra base is added to the All of the codons are changed from that point on, many
sequence. or all of the following amino acids will change
Deletion A base is removed from the All of the codons are changed from that point on, many
sequence or all of the following amino acids will change
mRNA Codon and corresponding amino acid table
Normal Gene
Non- mutated DNA AAA ATG TTT CTC CAA GAT
mRNA UUU UAC AAA GAG GUU CUA
Amino acid sequence coded for Phe Tyr Asn Asp Val Leu
Gene Mutation Problem 1: Substitution
In the following DNA sequence replace the G of the second codon with an A to create a new mutant DNA.
Determine the new mRNA sequence and the amino acid sequence.
Mutant DNA AAA ATA TTT CTC CAA GAT
mRNA UUU UAU AAA GAG GUU CUA
Amino acid sequence coded for Phe Tyr Asn Asp Val Leu
a) Describe the effect of the substitution mutation on the amino acid sequence of the protein
None, it is a silent mutation
Gene Mutation Problem 2: Deletion
In the following DNA sequence, a mutation of the same gene from the last example, a deletion mutation has
occurred. Refer to the “normal gene” on the previous page.
Mutant DNA AAA ATA TTC TCC AAG ATA
mRNA UUU UAU AAG AGG UUC UAU
Amino acid sequence coded for Phe tyr lys arg phe Tyr
b) Annotate (draw an arrow) showing the location of the deletion mutation.
c) Describe the effect on the amino acid sequence.
That ammino acid, and everyone after, is changed
Gene Mutation Problem 3: Determine the type and effect
In the following DNA sequence, a mutation of the same gene from the last example has occurred. Refer to the
“normal gene” on the previous page.
Mutant DNA AAA ATG TTT ACT CCA AGA
mRNA UUU UAC AAA UGA GGU UCU
Amino acid sequence coded for phe tyr lys stop gly ser
d) Annotate (draw an arrow) showing the location of the mutation.
e) Name this type of mutation.
insertion
f) Describe the effect of this mutation.
The bene is stopped from being read at that point. The protein is therefore cut short, as it is a shorter ammino acid
sequence.
