1. If histone H3 lysine 9 (H3K9) is extensively trimethylated across a chromosomal region in eukaryotic cells, what is the most likely functional consequence?

 Formation of transcriptionally silent heterochromatin

 Increased homologous recombination frequency

 Enhanced efficiency of mRNA translation

 Active transcription due to chromatin relaxation

2. A eukaryotic gene shows high transcription but low protein levels. The most plausible explanation is _______

 DNA methylation in the coding region

 Inactive promoter

 Lack of enhancer elements

 Post-transcriptional regulation

3. In eukaryotes, a gene’s promoter contains binding sites for three transcription factors, and transcription occurs only when all three are bound simultaneously. This regulatory strategy is known as _______

 Operon repression as in prokaryotic systems

 Combinatorial control, where specific combinations of factors determine expression

 Gene silencing that prevents transcription

 Attenuation leading to premature termination

4. A mutation that disrupts the function of spliceosome components would primarily affect ______________ in a eukaryotic cell

 Post-transcriptional mRNA processing

 Chromatin remodeling

 DNA replication

 Transcription initiation

5. Which RNA polymerase is responsible for synthesizing pre-mRNA (messenger RNA) in eukaryotes?

 RNA polymerase II

 RNA polymerase I

 RNA polymerase III

 Primase

6. In eukaryotes, enzyme ____________ synthesizes short RNA primers during DNA replication (not transcription)

 Ligase

 Primase

 RNA polymerase III

 RNA polymerase II

7. A transcription factor that recruits histone deacetylase (HDAC) will _______

 Enhance RNA stability

 Activate transcription

 Increase chromatin accessibility

 Promote gene repression via chromatin condensation

8. A mutation that disrupts the function of the TATA-binding protein (TBP) would most directly affect _______________________ in a eukaryotic cell?

 Formation of the transcription initiation complex

 RNA splicing

 Translation elongation

 Protein folding

9. Which RNA polymerase in eukaryotes is primarily responsible for synthesizing major ribosomal RNA (rRNA) precursors (except 5S rRNA)?

 RNA polymerase II

 RNA polymerase I

 RNA polymerase III

 Primase

10. During cellular differentiation, two cells have identical DNA but different phenotypes. This is primarily due to _______

 Chromosomal rearrangement

 Gene mutation

 Protein degradation errors

 Differential gene expression regulated epigenetically

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Question 1 of 10

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Gene Expression MCQs

Gene Expression is the process by which information encoded in DNA is converted into functional products—primarily proteins or functional RNAs.

It occurs in two main stages:

• Transcription: DNA is copied into messenger RNA (mRNA).
• Translation: mRNA is decoded by ribosomes to synthesize proteins.

Gene expression is tightly regulated at multiple levels (epigenetic, transcriptional, post-transcriptional, and translational), allowing cells to control when, where, and how much of a gene product is produced, which underlies cell differentiation, development, and environmental responses.