Download Mutations Worksheet

Point Mutations Practice
Name
Per. ___________
There are several types of genetic point mutations (a change in only one letter of the genetic code):
FRAMESHIFT, meaning the reading “frame” changes, changing the amino acid sequence.
DELETION (a base is lost)
INSERTION (an extra base is inserted)
SUBSTITUTION (one base is substituted for another)
If a substitution changes the amino acid, it’s called a MISSENSE point mutation.
If a substitution does not change the amino acid, it’s called a SILENT point mutation.
If a substitution changes the amino acid to a “stop”, it’s called a NONSENSE point mutation.
Complete the boxes below. Classify each as either Frameshift or Substitution mutations, then specify further
with Deletion, Insertion, or type of substitution. Use the chart on p. 303 in your textbook or back of Protein
synthesis notes to determine the amino acid sequence. Remember, RNA has Uracil instead of Thymine.
Original DNA Sequence:
T A C A C C T T G G C G
A C G A C T
mRNA Sequence:
___________________________________________________________________
Amino Acid Sequence (use 3-letter abbreviation):
Mutated DNA Sequence #1: (Circle the change) T
A
C
A
T
C
T
T
G
G
C
G
A
C
G
A
C
T
What’s the new mRNA sequence?
What will be the changed amino acid sequence?
What kind of mutation is this? ________________________________ sub-type? ____________________________________
Describe effects ______________________________________________________________________________________________
Mutated DNA Sequence #2 (from original DNA): T
A
C
G
A
C
C
T
T
G
G
C
G
A
C
G
A
C
T
What’s the new mRNA sequence?
What will be the changed amino acid sequence?
What kind of mutation is this? ________________________________ sub-type? ____________________________________
Describe effects ______________________________________________________________________________________________
Mutated DNA Sequence #3: (from original DNA): T
A
C
A
C
C
T
T
C
G
C
G
A
C
G
A
C
T
What’s the new mRNA sequence?
What will be the changed amino acid sequence?
What kind of mutation is this? ________________________________ sub-type? ____________________________________
Describe effects ___________________________________________
Mutated DNA Sequence #4: (from original DNA): T
A
C
A
C
C
T
T
G
G
C
G
A
C
A
A
C
T
What’s the new mRNA sequence?
What will be the changed amino acid sequence?
What kind of mutation is this? ________________________________ sub-type? ____________________________________
Describe effects ______________________________________________________________________________________________
Mutated DNA Sequence #5: (from original DNA): T
A
C
A
C
C
T
T
G
G
G
A
C
G
A
C
T
What will be the new mRNA sequence?
What will be changed the amino acid sequence?
What kind of mutation is this? ________________________________ sub-type? ____________________________________
Describe effects ______________________________________________________________________________________________
Analysis Questions:
1.
Which type(s) of mutation results in the most devastating change to the protein? Explain for each
2.
Which type(s) of mutation(s) is/are responsible for new variations of a trait? Explain for each.
3.
Which types of mutations stop the translation of the mRNA? Explain for each.
4.
Mutations in which cells get passed down to offspring?