Question

In the following diploid I-P+O+Z+Y-/I+P+O+Z-Y+ the Beta-galactosidase gene is

Select one:

A. inducible

B. uninducible

C. constitutive

D. all of the above

E. none of the above

Answer 1

I-P+O+Z+Y-/I+P+O+Z-Y+

Beta-galactosidase cannot be produced from, I+P+O+Z-Y+ because it lacks a functional beta-galactosidase gene.

The cell having this genotype can produce functional lac repressor from I+P+O+Z-Y+, this repressor can inhibit the expression of I-P+O+Z+Y-, so this operon cannot be expressed in the absence of an inducer if the inducer is present it inhibits this lac repressor, so lac repressor cannot inhibit lac operon. and I-P+O+Z+Y- has a functional beta-galactosidase gene, since this beta-galactosidase is expressed in the presence of an inducer, expression of beta-galactosidase is inducible.

uninducible: no expression even in the presence of an inducer.

constitutive: expressed always.

A) inducible.