Question

1. Which is TRUE of inducible genes?

A. They are constitutively expressed

B. They include structural genes, such as flagella

C. They include housekeeping genes, such as RNA polymerase beta subunit

D. They are regulated by ribozymes

E. They are generally metabolic genes

2. Two component signal transduction systems generally transduce _____________

signals.

A. Endogenous signals

B. Virulence

C. Pheromone

D. Exogenous

E. DNA

3. An operator sequence is generally bound by activator proteins.

A. True

B. False

4. Which of the following scientists was credited for the operon theory?

A. Jacques Monod

B. Frederick Griffith

C. Lois Pasteur

D. James Watson

E. Marshall Nirenberg

5. The co-repressor of TrpR is chorismate

A. True

B. False

6. Full induction of the lac operon requires what?

A. LacI only

B. LacI and CRP-cAMP

C. CRP-cAMP only

D. Glucose

E. LacI, CRP-cAMP and aporepressor

7. Transcriptional regulators, such as LacI, commonly bind DNA as dimers or oligomers.

A. True

B. False

8. Which of the following is false of the araBAD operon?

A. It is a tricistron

B. It is controlled by a dual regulator

C. It is a catabolic operon

D. It is a biosynthetic operon

E. It is regulated by AraC

9. Which of the following is true of sigma factors?

A. They bind to operators

B. The form a holoenzyme with the ribosome

C. They repress gene expression

D. They bind promoters

E. They are found only in eukaryotes

10. Inversion of the promoter for fimA is an example of regulation at the level of

transcription.

A. True B. False

Answer 1

Ans.1- (E)

inducible genes are generally metabolic genes i.e., genes involved in metabolism. for example, beta galactosidase gene is an inducible gene whose expression is induced by presence of lactose/galactose.

Ans 2 - (D)

two component signal transduction system consists of membrane-bound histidine kinase that senses a specific environmental stimulus (exogenous signal) and a corresponding response regulator that mediates the cellular response by differential expression of target genes.

Ans - 3 False

An operator sequence is generally bound by repressor.

Ans. 4- (A)

Ans. 5 - false

The co-repressor of TrpR is tryptophan.