The lac in lac operon refers to

(1)lactose but not lactase

(2)lactase but not lactose

(3)lactobacillus but not lactose

(4)lactose as well as laevorotatory

The i-gene in lac operon refers to

(1)inducer

(2)inhibitor

(3)sometimes inducer sometimes inhibitor

(4)neither inducer nor inhibitor

For lactose metabolism

(1) all three gene products are required

(2) only regulator gene products are required

(3) only Beta-galactosidase are required

(4) Beta-galactosidase and permease are required

In lac operon, repressor is inactivated by

(1)interaction with enzyme

(2)interaction with protein

(3)interaction with carbohydrate

(4)interaction with nucleic acid

How long the lac operon would be expressed in the presence of lactose?

(1) When glucose is more than lactose concentration

(2) As long as lactose is more than galactose concentration

(3) As long as lactose is more than glucose concentration

(4) when lactose equals glucose concentration

Lac operon is an example of

(1) both positive and negative regulation

(2)only negative regulation

(3)only positive regulation

(4)sometimes positive sometimes negative

Lac operon inhibition by repressor is an example of

(1) negative regulation

(2)positive regulation

(3)neither positive nor negative

(4) both positive and negative regulation

Regulation of lac operon can be visualised as regulation of enzyme synthesis by its

(1) substrate

(2)lactose

(3)carbohydrates

(4)All of these

Lac operon will be switched on when

(1) lactose is less in the medium

(2)glucose is enough in the medium

(3)lactose is less than glucose

(4)lactose is more than glucose

Repressor mRNA will be formed in

(1) absence of inducer

(2) presence of inducer

(3) both 1 and 2

(4) presence of lac mRNA