Q.1
In case of transcription which is the rate limiting step?
  • a) Binding of RNA polymerase
  • b) Unwinding of DNA duplex
  • c) Promoter escape
  • d) Formation of the open complex
Q.2
The site where repressor binds the DNA is the ______________
  • a) Promoter
  • b) Terminator
  • c) Operator
  • d) ORF
Q.3
Recruitment of RNA polymerase to the promoter is a ___________
  • a) Covalent binding
  • b) Cooperative binding
  • c) Protein-protein interaction
  • d) Van der Waals forces
Q.4
The proteins of which of the following genes are regularly needed for cellular activity?
  • a) Regular genes
  • b) Smart genes
  • c) Structural genes
  • d) Housekeeping genes
Q.5
Which of the following are the products of the constitutive gene?
  • a) i and ii
  • b) ii and iii
  • c) iii and iv
  • d) i, ii, iii and iv
Q.6
Which of the following is not an example of allosteric regulation?
  • a) Inactivation of nitrogenase by ADP ribosylation
  • b) Catabolite repression by CAP in E. coli
  • c) Regulation of phosphofructokinase activity
  • d) Regulation of lac operon by allolactose
Q.7
Operons are ___________
  • a) of approximately uniform size
  • b) found in some eukaryotes
  • c) not able to bind to proteins
  • d) smaller in lower eukaryotes and longer in higher eukaryotes
Q.8
Which of the following are correct according to operons?
  • a) i and ii
  • b) ii and iii
  • c) iii and iv
  • d) i, ii, iii and iv
Q.9
Choose the correct pair among the following.
  • a) The DNA sequence to which stigma factor binds – enhancer
  • b) The DNA sequence to which RNA polymerase binds – operator
  • c) The DNA sequence that codes for a protein – structural gene
  • d) The DNA sequence to which repressors binds – promoter
Q.10
Which of the following is not present in the β-galactosidase structural gene and thus is not transcribed by the same promoter?
  • a) Lac A
  • b) Lac I
  • c) Lac Z
  • d) Lac Y
Q.11
Glucose, as the carbon source, is the first choice by bacteria even if other sugars are available. The mechanism behind this selectivity is ___________
  • a) Operon repression
  • b) Glucose utilization
  • c) Enzyme repression
  • d) Catabolite repression
Q.12
The lac operon is regulated by cAMP by ___________
  • a) Binding to lac repressor
  • b) Binding to operator
  • c) Binding to promoter
  • d) Binding to catabolite activator protein
Q.13
Tryptophan operon in E. coli is a repressible operon.
  • a) True
  • b) False
Q.14
Which of the following is true about tryptophan operon?
  • a) Tetramer of identical subunits
  • b) The RNA product is very stable
  • c) The Trp repressor binds to the tryptophan
  • d) The Trp repressor is the product of the Trp operon
Q.15
The expression of the tryptophan operon is independent of the availability of tryptophan in culture media.
  • a) True
  • b) False
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