DNA Mutations Practice Worksheet
DIRECTIONS: Using the original DNA sequence, give the amino acid sequence. Then, do the same
for each mutated DNA sequence. Then, determine the consequence, if any, for each mutation, by
circling your choice for each question. You will need the DNA “word” Chart.
Original DNA
sequence:
ATG CAA AAC CGC
TGC TGA
amino acids:
Mutated DNA
sequence #1:
ATG CAG AAC CGC TGC TGA
amino acids:
Type of
mutation
(Circle one.)
How did the
mutation affect
the amino acid
sequence
(protein)?
(Circle one.)
Substitution
No change
Original DNA
sequence:
1 amino
acid
changed
Addition
Premature
stop signal
No stop
signal
ATG CAA AAC CGC
1 amino acid
added/
deleted
or
Deletion
All the amino acids
changed after the
point of mutation
TGC TGA
amino acids:
Mutated DNA
sequence #2:
ATG CAA ACC GCT GCT GA
amino acids:
Type of
mutation
(Circle one.)
How did the
mutation affect
the amino acid
sequence
(protein)?
(Circle one.)
Substitution
No change
1 amino
acid
changed
Addition
Premature
stop signal
No stop
signal
1 amino acid
added/
deleted
or
Deletion
All the amino acids
changed after the
point of mutation
Original DNA
sequence:
ATG CAA AAC CGC
TGC TGA
amino acids:
Mutated DNA
sequence #3:
ATG CAA AAC CCG CTG CTG A
amino acids:
Type of
mutation
(Circle one.)
How did the
mutation affect
the amino acid
sequence
(protein)?
(Circle one.)
Substitution
No change
Original DNA
sequence:
1 amino
acid
changed
Insertion
Premature
stop signal
No stop
signal
ATG CAA AAC CGC
1 amino acid
added/
deleted
or
Deletion
All the amino acids
changed after the
point of mutation
TGC TGA
amino acids:
Mutated DNA
sequence #4:
ATG CAA AAA CGC TGC TGA
amino acids:
Type of
mutation
(Circle one.)
How did the
mutation affect
the amino acid
sequence
(protein)?
(Circle one.)
Substitution
No change
1 amino
acid
changed
Insertion
Premature
stop signal
No stop
signal
1 amino acid
added/
deleted
or
Deletion
All the amino acids
changed after the
point of mutation
Original DNA
sequence:
ATG CAA AAC CGC
TGC TGA
amino acids:
Mutated DNA
sequence #5:
ATG CAA AAC CGC TGA TGA
amino acids:
Type of
mutation
(Circle one.)
How did the
mutation affect
the amino acid
sequence
(protein)?
(Circle one.)
Substitution
No change
(Silent)
1 amino
acid
changed
Insertion
Premature
stop signal
No stop
signal
1 amino acid
added/
deleted
or
Deletion
All the amino acids
changed after the
point of mutation
CONCLUSIONS
1. Which type of mutation result in no change to the amino acid sequence? Why is it that this mutation does not
change the amino acid sequence?
2. Which type of mutation can be neutral and cause no harmful effects on the organism? Why?
3. Which type (s) of mutation results in abnormal amino acid sequences?
4. Which type(s) of mutation cause harmful effects on the organism and why?
4. Examine your genetic code chart. Name one amino acid that has more than one codon. Name an amino acid that
has only one codon.
5. Look at the following sequence: THE FAT CAT ATE THE RAT. Delete the first H and regroup the letters in groups of
three- write out the new groups of three. Does the sentence still make sense? What type of mutation is this an
example of?