Cell Biology Questions and Answers – Gene Expression Control – Transcriptional-level Control

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This set of Cell Biology Multiple Choice Questions & Answers (MCQs) focuses on “Gene Expression Control – Transcriptional-level Control”.

1. Which technology can be used to monitor thousands of genes in a single experiment?
a) Centrifugation
b) Polymerase chain reaction
c) DNA microarrays
d) RNA microarrays
View Answer

Answer: c
Explanation: DNA microarrays (or “DNA chips”) is the technology that can be used to monitor the expression of thousands of genes expressed in a cell population, in a single experiment.
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2. How many types of transcription factors assist in transcription-level control?
a) 1
b) 2
c) 3
d) 4
View Answer

Answer: a
Explanation: There are two types of transcription factors, one that bind at the promoter sites in association with RNA polymerases and other that bind to regulatory sites of genes.

3. Sequence-specific transcription factors can act as transcriptional activators or repressors.
a) True
b) False
View Answer

Answer: a
Explanation: Sequence-specific transcription factors can act as transcriptional activators by stimulation the expression of adjacent gene or as transcriptional repressors by inhibiting its transcription.

4. What percent of genes encode transcription factors?
a) 5-10
b) 15-20
c) 40-50
d) 50-60
View Answer

Answer: a
Explanation: Approximately 5 to 10 percent of the genome encodes for transcription factors. One transcription factor interacts with more than one DNA sequence.

5. Which cells are pluripotent?
a) nucleosomes
b) embryonic stem cells
c) neurons
d) hepatocytes
View Answer

Answer: b
Explanation: Embryonic stem cells appear very early in the development of a mammalian embryo and possess two very unique properties, indefinite self-renewal and capability of differentiating into different cell types.
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6. Importance of transcription factors in embryonic stem cells was demonstrated in ______________
a) 1990
b) 1994
c) 2000
d) 2006
View Answer

Answer: a
Explanation: The importance of transcription factors in the biology of embryonic stem cells was demonstrated in 2006 Shinya Yamanaka and Kazutoshi Takahashi.

7. In cellular reprogramming, which of the following is removed during chromatin reorganization?
a) epigenetic marks
b) histones
c) lysosomes
d) nucleosomes
View Answer

Answer: a
Explanation: During cellular reprogramming, the epigenetic marks that include histone modifications and DNA methylation patterns of differentiated cells are replaced with that of pluripotent cells.

8. How many domains are present in a transcription factor?
a) 1
b) 2
c) 3
d) 4
View Answer

Answer: b
Explanation: The transcription factors usually contain two domains, activation domain that interacts with other DNA-binding proteins thereby regulating transcription, and DNA-binding domain that binds to the DNA sequence.

9. Motifs are related structures present on the transcription factors constituting the _________________ domain.
a) Activation
b) DNA-binding
c) RNA-binding domain
d) Nucleic acid-binding
View Answer

Answer: b
Explanation: The DNA-binding domains of various transcription factors contain related structures (believed to be conserved through evolutionary period) called motifs. The most common motifs in eukaryotes include zinc finger, the helix–loop–helix, and the leucine zipper.
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10. In the leucine-zipper motif, leucine occurs after every ____ amino acids.
a) 2
b) 4
c) 6
d) 8
View Answer

Answer: c
Explanation: In the leucine-zipper motif, the leucines occur every seventh amino acid along the length of alpha-helix. The alpha-helix is the part of the DNA-binding domain that fits into the major groove of DNA.

11. One of the key-enzymes involved in gluconeogenesis is ______________
a) phosphoenolpyruvate carboxykinase
b) phosphoenolpyruvate carboxylase
c) phosphoenolpyruvate ethanol
d) phosphoenolpyruvate esterase
View Answer

Answer: a
Explanation: One of the key enzymes involved in the metabolic pathway that converts pyruvate to glucose (gluconeogenesis) is phosphoenolpyruvate carboxykinase, synthesized in the liver when glucose levels are low.

12. Core promoter is the site that stretches between _______________
a) TATA box and start site
b) TATA box and stop site
c) TATA box and operator
d) TATA box and the promoter
View Answer

Answer: a
Explanation: Core promoter is the region upstream of a gene that stretches between the TATA box and the transcription start site. It is the site of assembly for pre-initiation complex consisting of RNA polymerase II and general transcription factors that are required for eukaryotic gene transcription.

13. CAAT and GC box are ________________
a) stop codons
b) promoter sequences
c) inhibitor sequences
d) operator sequences
View Answer

Answer: b
Explanation: Like TATA box, CAAT and GC box are short promoter sequences that are located farther upstream of the gene. These sequences are often required by the polymerase to initiate transcription of the gene.
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14. Which of the following is a transcription factor widely employed in eukaryotic gene expression?
a) NE1
b) NF1
c) NF2
d) NF3
View Answer

Answer: b
Explanation: NF1 is a transcription factor that binds to CAAT and GC boxes, found in many tissues and widely employed in eukaryotic gene expression.

15. TATA box regulates the frequency with which the gene is transcribed.
a) True
b) False
View Answer

Answer: b
Explanation: TATA box determines the site of the ignition of transcription whereas the frequency with which RNA polymerase transcribes a gene is determined by the CAAT and GC boxes.

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Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He is Linux Kernel Developer & SAN Architect and is passionate about competency developments in these areas. He lives in Bangalore and delivers focused training sessions to IT professionals in Linux Kernel, Linux Debugging, Linux Device Drivers, Linux Networking, Linux Storage, Advanced C Programming, SAN Storage Technologies, SCSI Internals & Storage Protocols such as iSCSI & Fiber Channel. Stay connected with him @ LinkedIn