1. Which of the following statements is not correct?
a) Bacteria possess only one type of RNA polymerase
b) Attenuation is a regulatory process used by bacteria to control the initiation of transcription
c) Repressor binds to operator
d) Bacterial genes are polycistronic
2. Which of the following bacterial operon is not controlled by attenuation?
3. Which of the following is the most appropriate definition of an operator?
a) A non-coding, regulatory DNA sequence that is bound by RNA polymerase
b) A non-coding, regulatory DNA sequence that is bound by a repressor protein
c) A DNA-binding protein that regulates gene expression
d) A cluster of genes that are regulated by a single promoter
4. To which class of transcription factor do nuclear receptors belong?
a) Zinc finger proteins
b) Leucine zipper proteins
c) Helix-turn-helix proteins
d) Helix-loop-helix proteins
5. Which of the following statements about lac operon in e.coli is true?
a) Promoter is the binding site for the lac repressor
b) Operon is only switched on in the absence of lactose in the growth medium
c) β-galactosidase is only produced in large quantities when the lac repressor is bound to the operator
d) Lac operon mRNA is a polycistronic mRNA