Practice quizzes

Question 1

Which of the following definitions best describes the protein produced by the regulator gene given that it has negative Control in a repressible Operon?

Answer 1

Inactive repressor

Question 2

A mutation prevents CAP (Catabolite Activator Protein) from binding to the lac operon, what is the effect?

Question 3

What is produced from the following lac operon in the presence of lactose:

lacI–lacP+lacO+lacZ+lacY–/
lacI+lacP–lacO+lacZ–lacY+

Answer 3

Beta galactosidase

Question 4

A lac operon with the Oc mutation will produce beta galactosidase and permease (given that Y and Z loci are intact):

Answer 4

In the presence or absence of lactose

Question 5

Which condition would produce the most and least amount of B-galactosidase, respectively?

Condition:

Lactose Present

Glucose Present

I

Yes

No

II

No

Yes

III

Yes

Yes

IV

No

No

Answer 5

I, II

Question 6

A mutant strain of E-coli produces beta-galactosidase in both the presence and absence of lactose. Where in the operon might the mutation be located?

Answer 6

LacO

Question 7

The protein produced by the regulatory gene in a repressible operon with negative control will be active.

Answer 7

False

Question 8

Identify the operon that would satisfies the following:

Beta-Galactosidase

Permease

Lactose Absent

None

None

Lactose Present

Present

None