Practice Questions

  1. Home
  2. Free Resources
  3. Practice Questions
  4. 4327
TLS Online TPP Program

#Question id: 4540

Transcription of eukaryotic genes can be repressed in various ways. These include the four mechanisms

1. Competition

a-Repression is caused by recruiting histone modifiers that alter nucleosomes in ways that inhibit transcript

2. Inhibition

b-A repressor binds to a site on DNA beside an activator and interacts with that activator, occluding its activating region

3. Direct repression

c-By binding to a site on DNA that overlaps the binding site of an activator, a repressor can inhibit binding of the activator to a gene and thus block activation of that gene.

4. Indirect repression

d-A repressor binds to a site upstream of a gene and, by interacting with the transcriptional machinery at the promoter in some specific way, inhibits transcription initiation.


#Unit 3. Fundamental Processes

  1. 1-a, 2-b, 3-c, 4-d

  2. 1-c, 2-b, 3-d, 4-a

  3. 1-b, 2-c, 3-a, 4-d

  4. 1-a, 2-c, 3-b, 4-d

More Questions
TLS Online TPP Program

#Question id: 4550

#Unit 3. Fundamental Processes

Which one of the following factor of Holoenzyme assists the RNA polymerase in separating the DNA strands at the transcription start site?
TLS Online TPP Program

#Question id: 4551

#Unit 3. Fundamental Processes

Various types of σ factor in column I, that are involved in several other function given in column II

 I

II

I) σ70

a) Induced by unfolded proteins in the cytoplasm contain chaperones activity which refold unfolded proteins               

II) σs

b) Genes involved in flagellum assembly             

III) σ32

c) Genes for nitrogen metabolism and other functions

IV) σE

d) Housekeeping genes, most genes in exponentially replicating cells

V) σF

e) Activated by unfolded proteins in the periplasmic space and cell membrane; genes encoding proteins that restore integrity to the cellular envelope

VI) σ54

f) Stationary-phase genes and general stress response

 Which of the following combination is correct?
TLS Online TPP Program

#Question id: 4552

#Unit 3. Fundamental Processes

The sequence of σ54 is distinctly different from that of all the σ70-like factors, some characteristics about σ54 is given below;

a) The σ54-RNA polymerase binds to the glnA promoter and immediately melt the DNA strands and initiate transcription

b) σ54-polymerase does not require ATP hydrolysis to separate the strands at a start site only require activator such as   NtrC

c) σ54-RNA polymerase initiate transcription of glnA promoter only when it is activated by NtrC

d) ATP hydrolysis is required for activation of bound σ54-RNA polymerase by phosphorylated NtrC

Which of the following from the bove combination is INCORRECT?
TLS Online TPP Program

#Question id: 4553

#Unit 3. Fundamental Processes

The NtrC protein (nitrogen regulatory protein C)—stimulates transcription of the glnA gene, this protein is an activator of σ54-RNA polymerase. Which of the following given characteristics about this protein is incorrect?
TLS Online TPP Program

#Question id: 4554

#Unit 3. Fundamental Processes

In which studies have shown that phosphorylated NtrC bound at enhancers and σ54-polymerase bound at the promoter interact directly, forming a loop in the DNA between the binding sites?
TLS Online TPP Program

#Question id: 4555

#Unit 3. Fundamental Processes

The σ54-RNA polymerase binds to the glnA promoter but does not melt the DNA strands and initiate transcription until it is activated by