Given the sentence "THE FAT CAT ATE THE RED RAT," which of the following would represent a frameshift mutation?

Question

A.  THE FAT RAT ATE THE RED CAT
B.  THE CAT ATE THE RED RAT
C.  THE FAC ATA TET HER EDR AT
D.  THE FAT CAT ATE THE RED RAT

Clarify Question
· What is the key concept addressed by the question?
· What type of thinking is required?
· What key words does the question contain and what do they mean?

Gather Content
· What do you already know about frameshift mutations?

Consider Possibilities
· Consider the different answer options. Which can you rule out?

Choose Answer
· Given what you now know, what information and/or problem solving approach is most likely to produce the correct answer?

Reflect on Process · Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?

Answer 1

C.  THE FAC ATA TET HER EDR AT

Clarify Question
· What is the key concept addressed by the question?
        o This question addresses frameshift mutations.
· What type of thinking is required?
        o This question is asking you to take what you already know and apply it to this unfamiliar situation.
· What key words does the question contain and what do they mean?
        o A frameshift mutation is a change in the DNA that shifts the reading frame.

Gather Content
· What do you already know about frameshift mutations?
        o A framshift mutation causes the bases to be read in different groups of three, so that the new codons no longer encode the same amino acids.
        o An insertion or deletion of nucleotides will cause a frameshift – unless it happens to insert or delete three nucleotides or a multiple of three.

Consider Possibilities
· Consider the different answer options. Which can you rule out?
        o Does a frameshift mutation switch around portions of the gene? No. So you can rule out the answer that switches CAT and RAT.
        o Is a three nucleotide deletion a type of frameshift mutation? No, because despite the deletion the reading frame further on stays the same. So you can rule out THE CAT ATE THE RED RAT.
        o Can a frameshift mutation appear to have no effect? No, it has a dramatic effect and you can see the shift in the sequence. So you can rule out the answer THE FAT CAT ATE THE RED RAT.

Choose Answer
· Given what you now know, what information and/or problem solving approach is most likely to produce the correct answer?
        o What is a frameshift mutation in DNA? An insertion or deletion that shifts the reading frame.
        o What is the result of a frameshift mutation? It changes the codons downstream of the mutation, usually into gibberish (wrong amino acids that don’t make a functioning protein).
        o So the answer option THE FAC ATA TET HER EDR AT is a good representation of a frameshift mutation. A single nucleotide deletion causes a shift in the frame that turns the codons downstream into gibberish.

Reflect on Process · Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?
        o This question asked you to choose the option that represents a frameshift mutation.
        o The question required you to take what you already know and apply it to this unfamiliar situation.
        o Did you recognize that the key feature of a frameshift mutation is that it shifts the reading frame, messing up all the codons downstream?