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A mutation changes a codon from UCG to UAG. This mutation is a:
Missense mutation
Silent mutation
Frameshift mutation
Nonsense mutation
Certain mutations in the DNA polymerase delta gene can lead to reduced fidelity of DNA replication. Which of the following would be the MOST LIKELY direct consequence of such a mutation?
Decreased rate of Okazaki fragment synthesis
Inhibition of DNA unwinding by helicase
Increased rate of DNA repair mechanisms
Increased mutation rate in the newly synthesized DNA
Imagine a prokaryotic organism with a mutated DNA polymerase III that lacks 3' to 5' exonuclease activity. What would be the MOST LIKELY consequence of this mutation?
Slower replication fork movement
Inability to initiate DNA replication
A higher rate of mutations in the replicated DNA
Increased formation of Okazaki fragments
Certain mutations in tRNA can suppress nonsense mutations in mRNA. This phenomenon is MOST directly related to alterations in which part of the tRNA?
Acceptor stem
D-loop
T\u03a8C loop
Anticodon loop
Which of these scenarios would MOST likely lead to a frameshift mutation that affects the downstream amino acid sequence?
Substitution of one nucleotide for another
Deletion of three nucleotides in the coding sequence
Insertion of two nucleotides in the coding sequence
Inversion of a segment of DNA containing a multiple of three nucleotides
A mutation in a eukaryotic gene results in the production of a truncated protein lacking its C-terminal region. Analysis reveals a mutation within an intron of the gene. Which of the following is the MOST likely explanation?
The mutation disrupted a splicing enhancer sequence, leading to exon skipping.
The mutation created a new promoter within the intron.
The mutation disrupted the polyadenylation signal, preventing proper termination.
The mutation created a premature stop codon within the intron.
A frameshift mutation occurs in a gene encoding a crucial enzyme. Which of the following is the LEAST likely consequence?
A silent mutation resulting in no change to the enzyme's function.
A truncated, non-functional protein due to a premature stop codon.
An altered amino acid sequence leading to a change in enzyme activity.
A protein with a completely different amino acid sequence and function.
Certain mutations are referred to as 'suppressor mutations.' Which statement best describes their function?
They increase the rate of other mutations within the same gene.
They always revert the original mutation back to the wild-type sequence.
They reverse the phenotypic effect of another mutation at a different site within the same gene or a different gene.
They enhance the phenotypic expression of the original mutation.
Which of the following DNA repair mechanisms is MOST likely to be involved in correcting a thymine dimer caused by UV radiation?
Base Excision Repair
Mismatch Repair
Nucleotide Excision Repair
Homologous Recombination
A mutation changes a codon from UAU (Tyrosine) to UAC (Tyrosine). This is an example of which type of mutation?
Missense mutation
Nonsense mutation
Frameshift mutation
Silent mutation
