A mutant E. coli strain, grown under conditions that normally induce the lac operon, does not produce ß-galactosidase. What is a possible genotype of the cells?
A. lacl+ lacP+ lacO+ lacZ+ lacY+ lacA+
B. lacI+ lacP+ lacOc lacZ+ lacY+ lacA+
C. lacI- lacP+ lacO- lacZ+ lacY+ lacA-
D. lacI+ lacP- lacO+ lacZ+ lacY+ lacA+
E. lacI+ lacP+ lacO+ lacZ+ lacY- lacA+
Ans: D. lacI+ lacP- lacO+ lacZ+ lacY+ lacA+
You might also like to view...
One key principle of natural selection is that there is competition for resources
A. true B. false
Match each toxin type below with its effect on the human host.
a. exotoxins b. endotoxins 1. have systemic effects such as fever, inflammation, diarrhea, and shock 2. have effects on a specific cell type
Each chromosome has one or more ________ site(s) where replication begins.
A. bifurcate B. promoter C. origin D. replicon
Which of the following structures allow aquatic bacteria to orient themselves in the Earth's magnetic field?
A) Carboxysomes B) Gas vacuoles C) Magnetosomes D) Polyphosphate granules