6. In positive regulation in bacteria, the gene is _______, however a regulator

Question

6. In positive regulation in bacteria, the gene is _______, however a regulator (i.e. an activator) must _______.

A. already on at some level/bind the regulatory DNA element and shut own transcription

B. already on at the basal level/bind the regulatory DNA element and activate transcription

C. turned off/ bind the regulatory DNA element and activate transcription

7. The basal level of transcription is done by the RNAP and the ______ without the help/intervention of the ______.

A. GTFs/activators

B. GTFs/ regulators                  

C. activators/repressors

D. repressors/ activators

8. In E. coli, there is only one RNAP, ___________________.

A. therefore, there is only one type of core promoter

B. but there can be several types of core promoters

C. but there are several types of enhancers and silencers

9. Which of the following is a typical inducer in the regulation of a gene in E. coli?

A. A protein that binds DNA

B. A chemical compound that binds an activator

C. A chemical compound that binds a repressor                  

D. A chemical compound that binds an activator or a repressor

10. In bacteria, the regulators are activators or repressors. At the end, the regulators affect transcription by ____________.

A. binding inducers

B. binding DNA and inducers                  

C. changing DNA conformation                  

D. affecting the frequency of successful transcription initiation

11. An E. coli operon has four genes. The operon generally should contain __________.

A. one promoter and one terminator

B. one promoter and up to four terminators

C. up to four promoters and one terminator                  

D. up to four promoters and up to four terminators

12. Expression of which of the following genes is constitutive?

A. GAPDH gene, the level of the protein product is same, irrespective of growth conditions or state of the cell

B. LacZ gene, the protein is absent in cells growing in the presence of glucose but abundant in cells growing in the presence of lactose

C. Bacteriocine, the protein is absent in healthy young log-phase cells but plentiful in old, slow-growing stationary phase cells.

13. Of the three genes GAPDH (always on), lacZ (on when there is no glucose inside the cell) and bacteriocine genes (when the cell is in the stationary phase of growth), the __________ gene is regulated temporally, and the _______ gene is regulated spatially.

A. GAPDH/ LacZ

B. lacZ/bacteriocene

C. bacteriocene/lacZ

D. bacteriocene/GAPDH

14. Which of the following defines isomerization?

A. Substance P changed shape (conformation) but remained substance P

B. Substance P changed to substance Q and lost its identity (of being P)

C. Substance P reacted with substance Q and formed substance R

Explanation / Answer

6. B.

7. B

8. A

9. D (inducer binds to both activator and repressor)

10. A (inducer binds to regulators)

11. A (one promoter and one terminator)

12. A

13. C

14. A

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