Multiple Choice
In the context of gene mutations, what type of mutation typically causes translation of an mRNA to stop prematurely by creating a stop codon within the coding sequence?
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17. Mutation, Repair, and Recombination
Types of Mutations
Multiple Choice
In the context of types of mutations, which type of mutation is most likely to result in an abnormal amino acid sequence downstream of the mutation site?
A
Silent (synonymous) mutation that does not change the encoded amino acid
B
Missense mutation that substitutes one amino acid for another but does not alter the reading frame
C
Frameshift mutation caused by an insertion or deletion not in multiples of three nucleotides
D
Mutation in an intron that is spliced out and therefore does not affect the coding sequence
Verified step by step guidance1
Step 1: Understand the types of mutations listed and their effects on the amino acid sequence. Silent mutations do not change the amino acid sequence, so they do not affect the downstream sequence.
Step 2: Recognize that missense mutations change one amino acid to another but do not affect the reading frame, so only one amino acid is altered, not the entire downstream sequence.
Step 3: Recall that frameshift mutations occur when insertions or deletions are not in multiples of three nucleotides, which shifts the reading frame of the codons.
Step 4: Understand that a frameshift mutation changes every amino acid downstream of the mutation site because the triplet codon reading frame is altered, leading to an abnormal amino acid sequence.
Step 5: Note that mutations in introns usually do not affect the coding sequence because introns are spliced out before translation, so they typically do not change the amino acid sequence.
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