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A mutation in the lac operon's promoter region increases its affinity for RNA polymerase. In the presence of both glucose and lactose, how will the expression levels of the lac operon genes be affected compared to a wild-type strain?
No change in expression compared to wild-type.
Increased expression compared to wild-type, but not maximal expression.
Maximal expression of the lac operon genes.
Complete repression of the lac operon genes.
If a mutation occurs in the operator region of the lac operon such that the repressor protein can no longer bind, which of the following scenarios would still result in reduced lac operon expression compared to maximal induction?
Absence of glucose, presence of lactose
High glucose, presence of lactose
Absence of glucose, absence of lactose
High glucose, absence of lactose
In an environment containing both lactose and glucose, a mutation in the gene encoding adenylate cyclase renders it permanently inactive. What would be the primary consequence for lac operon expression?
Constitutive expression
Significantly reduced expression despite the presence of lactose
Expression levels similar to wild-type in the presence of only lactose
No change in expression compared to wild-type
A researcher engineers a strain of E. coli where the CAP binding site upstream of the lac operon promoter is deleted. In an environment lacking glucose and containing lactose, what would be the observed expression level of the lac operon genes compared to a wild-type strain under the same conditions?
Significantly reduced
Slightly reduced
No change
Significantly increased
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
Transposons, also known as 'jumping genes,' can cause mutations by:
Always causing frameshift mutations.
Only occurring in germ cells.
Inserting themselves into a gene, disrupting its function.
Exclusively causing point mutations.
Which type of mutation is MOST likely to result in a protein with a completely new function?
Silent mutation
Missense mutation in a non-coding region
Frameshift mutation in a coding region
Nonsense mutation at the very end of a coding region
