- What is the primary level of gene expression regulation in prokaryotes?
A. Transcriptional level
B. Translational level
C. Post-transcriptional level
D. Epigenetic level
Answer: A. Transcriptional level - Which of the following is an operon found in prokaryotes?
A. Lac operon
B. Enhancer operon
C. Spliceosome operon
D. Chromatin operon
Answer: A. Lac operon - What is the role of the repressor protein in the lac operon?
A. Activates transcription
B. Inhibits transcription
C. Stabilizes mRNA
D. Enhances translation
Answer: B. Inhibits transcription - In eukaryotes, gene regulation is influenced by which chromatin modification?
A. Phosphorylation
B. Acetylation
C. Hydroxylation
D. Glycosylation
Answer: B. Acetylation - What is the function of a promoter in gene expression?
A. Terminates transcription
B. Initiates transcription
C. Enhances translation
D. Silences mRNA
Answer: B. Initiates transcription - What type of molecule acts as an inducer in the lac operon?
A. cAMP
B. Allolactose
C. Glucose
D. ATP
Answer: B. Allolactose - In eukaryotic cells, enhancers are DNA sequences that:
A. Bind RNA polymerase
B. Increase transcription rates
C. Terminate transcription
D. Decrease transcription rates
Answer: B. Increase transcription rates - Which enzyme is responsible for relaxing chromatin structure?
A. Histone deacetylase
B. DNA polymerase
C. Histone acetyltransferase
D. RNA polymerase
Answer: C. Histone acetyltransferase - The trp operon is an example of:
A. Inducible operon
B. Repressible operon
C. Constitutive operon
D. Post-transcriptional operon
Answer: B. Repressible operon - The sigma factor in prokaryotic transcription helps in:
A. DNA replication
B. Transcription initiation
C. RNA splicing
D. Translation termination
Answer: B. Transcription initiation
- Which of the following is a post-transcriptional regulatory mechanism in eukaryotes?
A. Alternative splicing
B. Enhancer activation
C. Operon repression
D. RNA editing
Answer: A. Alternative splicing - In prokaryotic gene regulation, what is the role of cAMP?
A. Binds to repressors
B. Activates CAP protein
C. Inhibits RNA polymerase
D. Degrades mRNA
Answer: B. Activates CAP protein - Which of the following RNA molecules regulate gene expression?
A. tRNA
B. mRNA
C. miRNA
D. rRNA
Answer: C. miRNA - Silencer sequences in eukaryotic DNA are responsible for:
A. Enhancing transcription
B. Suppressing transcription
C. Modifying RNA
D. Stabilizing proteins
Answer: B. Suppressing transcription - Epigenetic regulation involves modifications to:
A. mRNA sequence
B. Amino acid sequence
C. DNA or histones
D. Ribosome structure
Answer: C. DNA or histones - What is the function of the leader peptide in the trp operon?
A. Enhances translation
B. Regulates attenuation
C. Initiates transcription
D. Binds RNA polymerase
Answer: B. Regulates attenuation - In eukaryotes, transcription factors bind to:
A. Ribosomes
B. Promoters and enhancers
C. Operons
D. Introns
Answer: B. Promoters and enhancers - The lac operon is fully activated when:
A. Glucose is present
B. Glucose is absent, and lactose is present
C. Lactose and glucose are both present
D. None of the above
Answer: B. Glucose is absent, and lactose is present - Which is not a mechanism of eukaryotic gene regulation?
A. RNA splicing
B. Chromatin remodeling
C. Sigma factor binding
D. DNA methylation
Answer: C. Sigma factor binding - What is the role of histone deacetylases (HDACs)?
A. Increase gene expression
B. Suppress gene expression
C. Facilitate splicing
D. Stabilize RNA
Answer: B. Suppress gene expression
- Attenuation in the trp operon is influenced by:
A. Ribosome stalling
B. RNA polymerase speed
C. DNA replication rate
D. Enhancer activation
Answer: A. Ribosome stalling - In eukaryotes, alternative splicing allows:
A. Formation of multiple proteins from a single gene
B. Elimination of introns
C. Binding of repressors
D. Termination of translation
Answer: A. Formation of multiple proteins from a single gene - CAP protein activation in prokaryotes requires:
A. Glucose
B. cAMP
C. ATP
D. Lactose
Answer: B. cAMP - Gene silencing by RNA interference involves:
A. tRNA
B. miRNA or siRNA
C. rRNA
D. RNA polymerase
Answer: B. miRNA or siRNA - Enhancers differ from promoters because they:
A. Bind repressors
B. Can act at a distance from the gene
C. Terminate transcription
D. Are found only in prokaryotes
Answer: B. Can act at a distance from the gene
- What is the main effect of DNA methylation?
A. Enhances gene expression
B. Suppresses gene expression
C. Initiates translation
D. Splices RNA
Answer: B. Suppresses gene expression - Prokaryotic gene expression is primarily regulated by:
A. mRNA stability
B. Transcriptional control
C. Protein folding
D. Chromatin remodeling
Answer: B. Transcriptional control - Histone acetylation is associated with:
A. Gene activation
B. Gene repression
C. Protein degradation
D. RNA interference
Answer: A. Gene activation - The presence of tryptophan in the trp operon results in:
A. Operon activation
B. Repressor activation
C. Enhanced transcription
D. Splicing of mRNA
Answer: B. Repressor activation - In prokaryotes, polycistronic mRNA allows:
A. Regulation of multiple genes in one operon
B. Alternative splicing
C. RNA editing
D. Intronic expression
Answer: A. Regulation of multiple genes in one operon**
These MCQs can help reinforce key concepts in gene expression regulation for both prokaryotic and eukaryotic systems.
