Question 21

(Multiple Choice)

Which is true about an operator constitutive (Oc)mutation?


A) An Oc mutation on the chromosome can affect the expression of structural genes on a plasmid.
B) The Oc mutation prevents the expression of a diffusible product that regulates the lac operon.
C) An F' I+P+ Oc Z-Y+A-/I+P+O+Z+Y+A+ merozygote expresses the enzymes of the lac operon constitutively.
D) The O? mutations act only in cis.
E) An F' I+P+ Oc Z+Y+A+/I+P+O+Z-Y-A- merozygote is inducible for the three enzymes of the lac operon.

Answer