1. What is the primary role of transcription factors in gene expression?
a) Replicating DNA
b) Initiating transcription
c) Synthesizing RNA
d) Editing RNA
Answer: b) Initiating transcription
Explanation: Transcription factors are proteins that bind to specific DNA sequences to control the transcription of genetic information from DNA to RNA. They are key players in initiating the process of transcription.
2. Which of the following is NOT a function of transcription factors?
a) Binding to DNA sequences
b) Recruiting RNA polymerase
c) Modifying the DNA sequence
d) Facilitating gene expression regulation
Answer: c) Modifying the DNA sequence
Explanation: Transcription factors do not modify the DNA sequence; they only bind to specific DNA regions and regulate the expression of genes.
3. Which component of a transcription factor is responsible for DNA binding?
a) Activation domain
b) Dimerization domain
c) DNA-binding domain
d) Transactivation domain
Answer: c) DNA-binding domain
Explanation: The DNA-binding domain is the part of a transcription factor that interacts directly with the promoter or enhancer regions of DNA to initiate transcription.
4. Which of the following is an example of a general transcription factor?
a) p53
b) TATA-binding protein (TBP)
c) CREB
d) NF-κB
Answer: b) TATA-binding protein (TBP)
Explanation: TBP is a general transcription factor that binds to the TATA box region of the promoter to initiate transcription by RNA polymerase.
5. Which of the following transcription factors is involved in cell cycle regulation?
a) NF-κB
b) p53
c) CREB
d) SP1
Answer: b) p53
Explanation: p53 is a transcription factor that regulates the cell cycle and can induce cell cycle arrest or apoptosis in response to DNA damage.
6. What type of molecule is a transcription factor?
a) Protein
b) RNA
c) Lipid
d) Carbohydrate
Answer: a) Protein
Explanation: Transcription factors are proteins that regulate the transcription of specific genes by binding to DNA.
7. Which transcription factor is involved in immune response regulation?
a) NF-κB
b) CREB
c) Myc
d) p53
Answer: a) NF-κB
Explanation: NF-κB is a transcription factor that plays a key role in immune responses and inflammation, regulating genes involved in these processes.
8. Which of the following elements is a common target for transcription factor binding?
a) Ribosome
b) Promoter
c) Mitochondria
d) Endoplasmic reticulum
Answer: b) Promoter
Explanation: Transcription factors commonly bind to the promoter region of genes to initiate or regulate transcription.
9. What is the role of enhancers in gene regulation?
a) Increase gene expression
b) Decrease gene expression
c) Replicate the DNA
d) Cut the DNA sequence
Answer: a) Increase gene expression
Explanation: Enhancers are regions of DNA that, when bound by transcription factors, enhance the transcription of associated genes.
10. What is the effect of a transcription factor mutation on gene expression?
a) No effect
b) Increased transcription only
c) Decreased or altered transcription
d) Gene expression will always be activated
Answer: c) Decreased or altered transcription
Explanation: A mutation in a transcription factor can lead to misregulation of target gene expression, resulting in either reduced or abnormal transcription.
11. Which of the following transcription factors is involved in neuronal development?
a) MyoD
b) CREB
c) Neuron-restrictive silencer factor (NRSF)
d) TATA-binding protein
Answer: c) Neuron-restrictive silencer factor (NRSF)
Explanation: NRSF is involved in the regulation of neuronal-specific genes, silencing them in non-neuronal cells.
12. Which of the following is a characteristic feature of activator transcription factors?
a) They repress gene expression.
b) They bind to enhancers to enhance gene transcription.
c) They prevent RNA polymerase binding to DNA.
d) They degrade mRNA.
Answer: b) They bind to enhancers to enhance gene transcription.
Explanation: Activator transcription factors bind to enhancer regions to increase the transcription of associated genes.
13. Which class of transcription factors is responsible for repressing gene expression?
a) Coactivators
b) Corepressors
c) General transcription factors
d) Transcriptional activators
Answer: b) Corepressors
Explanation: Corepressors are transcription factors that bind to promoters or enhancers and repress gene expression by preventing RNA polymerase binding or by recruiting repressive chromatin modifiers.
14. Which of the following transcription factors is commonly associated with stress response pathways?
a) CREB
b) NF-κB
c) p53
d) AP-1
Answer: d) AP-1
Explanation: AP-1 is a transcription factor that responds to various stress signals, such as oxidative stress, and regulates the expression of genes involved in these responses.
15. Which of the following is NOT a type of transcription factor binding motif?
a) Zinc finger
b) Helix-turn-helix
c) Leucine zipper
d) Actin filament
Answer: d) Actin filament
Explanation: Actin filaments are structural proteins, not transcription factor motifs. The other three are common DNA-binding motifs for transcription factors.
16. How do transcription factors affect chromatin structure?
a) By modifying histones
b) By breaking DNA strands
c) By forming ribosomes
d) By synthesizing DNA
Answer: a) By modifying histones
Explanation: Transcription factors can influence chromatin structure by recruiting enzymes that modify histones, which can either promote or inhibit transcription by altering chromatin accessibility.
17. What is the primary function of the transcription factor MyoD?
a) Regulation of immune response
b) Control of muscle cell differentiation
c) Cell cycle regulation
d) Apoptosis initiation
Answer: b) Control of muscle cell differentiation
Explanation: MyoD is a transcription factor that plays a central role in muscle cell differentiation, particularly in the development of skeletal muscle.
18. What is the role of the transcription factor Sp1?
a) Activation of tumor suppressor genes
b) Control of cell division
c) Regulation of genes involved in growth and apoptosis
d) Regulation of housekeeping genes
Answer: d) Regulation of housekeeping genes
Explanation: Sp1 is a transcription factor that binds to GC-rich motifs in the promoter regions of housekeeping genes, which are constitutively expressed in cells.
19. Which transcription factor is a key player in the hypoxic response?
a) NF-κB
b) HIF-1 (Hypoxia-Inducible Factor-1)
c) CREB
d) Myc
Answer: b) HIF-1 (Hypoxia-Inducible Factor-1)
Explanation: HIF-1 is a transcription factor that helps cells respond to low oxygen conditions by activating genes that adapt metabolism and angiogenesis.
20. Which of the following transcription factors regulates the synthesis of heat shock proteins?
a) NF-κB
b) Heat shock factor (HSF)
c) p53
d) CREB
Answer: b) Heat shock factor (HSF)
Explanation: HSF is a transcription factor that activates the transcription of heat shock proteins, which protect cells from stress-induced damage.
21. What does the transcription factor NFAT primarily regulate?
a) Immune responses
b) Cell differentiation
c) DNA replication
d) Apoptosis
Answer: a) Immune responses
Explanation: NFAT (Nuclear Factor of Activated T-cells) regulates genes involved in immune responses, particularly in T cells.
22. Which of the following describes the relationship between transcription factors and RNA polymerase?
a) Transcription factors prevent RNA polymerase from binding to DNA.
b) Transcription factors recruit RNA polymerase to the promoter.
c) RNA polymerase functions independently of transcription factors.
d) Transcription factors degrade RNA polymerase.
Answer: b) Transcription factors recruit RNA polymerase to the promoter.
Explanation: Transcription factors bind to DNA regions, such as promoters or enhancers, and help recruit RNA polymerase to initiate transcription.
23. Which of the following transcription factors is involved in embryonic development?
a) MyoD
b) Oct4
c) p53
d) NF-κB
Answer: b) Oct4
Explanation: Oct4 is a transcription factor that is crucial for maintaining pluripotency in stem cells and is involved in early embryonic development.
24. What is the role of the transcription factor E2F?
a) Regulation of cell differentiation
b) Promotion of cell cycle progression
c) Induction of apoptosis
d) Regulation of immune responses
Answer: b) Promotion of cell cycle progression
Explanation: E2F is a family of transcription factors that regulate the expression of genes required for the progression of the cell cycle, particularly from the G1 to S phase.
25. Which of the following is a property of transcription factors?
a) They are always active.
b) They are specific to only one gene.
c) They require cofactors for their activity.
d) They do not interact with DNA.
Answer: c) They require cofactors for their activity.
Explanation: Transcription factors often require cofactors, such as coactivators or corepressors, to exert their effects on gene expression.
26. Which of the following transcription factors is involved in regulating apoptosis?
a) p53
b) CREB
c) AP-1
d) Sp1
Answer: a) p53
Explanation: p53 is a transcription factor that can induce apoptosis in response to cellular stress, such as DNA damage.
27. What is the role of the transcription factor CREB?
a) Regulation of cell growth
b) Activation of stress response genes
c) Regulation of circadian rhythms and neuronal activity
d) Control of immune responses
Answer: c) Regulation of circadian rhythms and neuronal activity
Explanation: CREB is involved in regulating circadian rhythms, neuronal activity, and the expression of genes related to memory and learning.
28. Which of the following transcription factors is involved in the stress response pathway?
a) AP-1
b) HIF-1
c) CREB
d) NF-κB
Answer: a) AP-1
Explanation: AP-1 (Activator Protein-1) is involved in cellular responses to stress, such as oxidative stress or DNA damage.
29. Which of the following describes a characteristic of a repressor transcription factor?
a) It enhances gene expression by recruiting RNA polymerase.
b) It prevents transcription by binding to DNA regions.
c) It binds to enhancers to activate transcription.
d) It stabilizes the mRNA.
Answer: b) It prevents transcription by binding to DNA regions.
Explanation: Repressor transcription factors inhibit gene expression by binding to specific regions of DNA, such as silencers, and preventing transcription.
30. Which of the following transcription factors is known to regulate the immune system?
a) NF-κB
b) MyoD
c) CREB
d) SP1
Answer: a) NF-κB
Explanation: NF-κB is a key transcription factor in regulating immune responses and inflammation, controlling genes that promote these processes.
