1. In prokaryotes, the sigma (σ) factor is essential for ________________

 Splicing of tRNA

 Termination of transcription

 Translation initiation

 Recognition of the promoter by RNA polymerase

2. During translation elongation, ribosomal site ______________ directly binds the incoming aminoacyl-tRNA

 P site

 A site

 E site

 D site

3. The lac operon in E. coli is maximally activated under which condition?

 High glucose, presence of lactose

 High glucose, absence of lactose

 Low glucose, absence of lactose

 Low glucose, presence of lactose

4. Histone acetyltransferases (HATs) promote gene expression by directly __________________

 Removing methyl groups from histones

 Blocking RNA polymerase binding to DNA

 Reducing the affinity between histones and DNA

 Condensing chromatin structure

5. ___________________ transcribes tRNA and 5S rRNA genes in eukaryotic cells

 RNA polymerase II

 RNA polymerase III

 RNA polymerase I

 Helicase

6. In eukaryotic gene regulation, enhancer elements differ from promoters in that enhancers ________________

 Can function independently of position and orientation

 Bind RNA polymerase directly

 Are always located immediately upstream of the target gene

 Directly initiate transcription at the transcription start site

7. Transcription produces _______

 Protein

 Transfer RNA (tRNA)

 Messenger RNA (mRNA)

 DNA

8. Ribosomes are the site of _______

 DNA replication

 Protein synthesis

 Lipid synthesis

 RNA synthesis

9. A muscle cell and a liver cell from the same individual have identical DNA sequences but produce different proteins and exhibit distinct structures. This difference is primarily due to _______

 Chromosomal rearrangements unique to each cell type

 Random errors in protein degradation pathways

 Differential gene expression established by epigenetic regulation

 Gene mutations accumulated during development

10. In bacteria, the ribosome binding site on mRNA is called the __________________

 Shine–Dalgarno sequence

 TATA box

 Kozak sequence

 Poly(A) signal

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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.