The table below lists several genotypes associated with the lac operon in E. coli. For each, indicate with a "+" or a "-" whether functional ?-galactosidase would be expected to be produced at induced levels

?-Galactosidase Production
Genotype No Lactose With Lactose
(a) I + O+ Z+/F' I - O+ Z+
(b) I - Oc Z+/F' I - O+ Z-
(c) I s Oc Z+/F' I + O+ Z+
(d) I - O+ Z+/F' I - O+ Z+

I + = wild-type repressor
I - = mutant repressor (unable to bind to the operator)
I s = mutant repressor (insensitive to lactose)
O+ = wild-type operator
Oc = constitutive operator (insensitive to repressor)


(a) - +
(b) + +
(c) + +
(d) + +

Biology & Microbiology

You might also like to view...

Where does karyogamy occur in basidiomycetes?

a. basidia b. conidiophores c. sporangia d. asci e. zygospores

Biology & Microbiology

Osmoregulation is the control of

a. the internal environment. b. temperature. c. metabolic wastes. d. water and ion balance. e. hyperthermia.

Biology & Microbiology

Which lineage of Cnidarians includes adults that are predominately medusae and the true jellyfishes?

a. Anthozoa b. Hydrozoa c. Scyphozoa d. Cubozoa

Biology & Microbiology

Traditions, beliefs, and values are considered what aspect of human life?

A. cultural B. communicative C. biological D. instructional E. chemical

Biology & Microbiology