Name: ___________________________________________ Date: __________________ Period: _____
Code Cracking
Mutation Practice
Review:
Three of the most common types of mutations are:
1. POINT MUTATION (one base is substituted for another)
If a point mutation changes the amino acid, it’s called a MISSENSE mutation.
If a point mutation does not change the amino acid, it’s called a SILENT mutation.
If a point mutation changes the amino acid to a “stop,” it’s called a NONSENSE mutation.
2. INSERTION (an extra base, or bases, is inserted)
3. DELETION (a base, or bases, is lost)
Deletion and insertion may cause what’s called a FRAMESHIFT, meaning the reading frame changes.
These are typically one of the most serious types of mutations.
Directions:
1. Following the same procedure you followed during the decoding activity (DNA to mRNA to
Amino Acid), decode the original and mutated sequences and identify them as one of the three
types of mutations listed above. If it is a point mutations, include whether it is a missense, silent,
or nonsense mutations.
The original DNA sequence is:
DNA: TGC GTG CTT AAG CGG TGT ACA CGT TGC
mRNA:
Amino acid:
Symbol:
