Mutation and gene regulation revision Y13

A change in the nucleotide sequence of DNA is best described as a:

• Replication error

• Transcription error

• Mutation

• Translation error

Which type of point mutation results in a premature stop codon?

• Silent mutation

• Missense mutation

• Nonsense mutation

• Frameshift mutation

The insertion or deletion of a nucleotide in a gene sequence is most likely to cause a:

• Silent mutation

• Missense mutation

• Nonsense mutation

• Frameshift mutation

What is the role of transcription factors in gene regulation?

• They synthesize mRNA.

• They degrade mRNA.

• They bind to DNA and control the rate of transcription.

• They catalyze DNA replication.

In the lac operon of E. coli, what happens when lactose is present?

• The repressor binds to the operator, blocking transcription.

• Lactose binds to the repressor, causing it to detach from the operator, allowing transcription.

• RNA polymerase cannot bind to the promoter.

• The structural genes are not transcribed.

Which of the following is an example of a post-transcriptional modification of mRNA in eukaryotes?

• DNA replication

• Translation

• Splicing

• Transcription initiation

What is the role of regulatory genes in gene regulation?

• They code for structural proteins.

• They code for functional RNA molecules like tRNA.

• They code for proteins that control the expression of other genes.

• They are not involved in gene regulation.

Which type of mutation involves the exchange of segments between non-homologous chromosomes?

• Deletion

• Duplication

• Inversion

• Translocation

What is the effect of DNA methylation on gene expression in eukaryotes?

• It generally increases gene expression.

• It generally decreases gene expression.

• It has no effect on gene expression.

• It always leads to a frameshift mutation.

Which of the following is a potential cause of spontaneous mutations?

• Exposure to UV radiation

• Exposure to certain chemicals

• Errors during DNA replication

• All of the above