試題詳解

39. Three operators (O_R1, O_R2, O_R3) are located between the P_R and P_RMpromoters in the genome of bacteriophage λ. Which of the following are correct regarding these three operators?
(A) O_R1 is located within P_R, while O_R3 is located within PRM.
(B) All three operators can bind to either λ repressor or Cro.
(C) The binding affinity of the three operators to Cro is O_R1 ＞ O_R2 ＞ O_R3.
(D) X repressor at O_R1 helps the repressor bind to O_R2 by cooperative binding.
(E) Binding of λ repressor to O_R3 leads to increase in the λ repressor gene expression.