Gujarati
Hindi
5.Molecular Basis of Inheritance
medium

Select the two correct statements out of the four $(i-iv)$ given below about lac operon.

$i.$ Glucose or galactose may bind with the repressor and inactivate it.

$ii.$ In the absence of lactose, the repressor binds with the operator region.

$iii.$ The z-gene codes for permease.

$iv.$ This was elucidated by Francois Jacob and Jacque Monod.

A

$(ii)\; and\; (iii)$

B

$(i)\; and \;(iii)$

C

$(ii)\; and\; (iv)$

D

$(i)\; and\; (ii)$

Solution

Jacob and Monod proposed the lac operon of $E. coli.$ The lac operon contains a promoter, an operator, and three structural genes called $\mathrm{Z}, \mathrm{Y}$, and $\mathrm{A}$, coding for the enzyme, $b$ galactosidase, permease and transacetylase respectively. The lac regulator gene, designated as i gene, codes for repressor. In the absence of the inducer, the repressor binds to the lac operator, preventing $RNA$ polymerase from binding to the promoter and thus transcribing the structural gene.

Standard 12
Biology

Similar Questions

Start a Free Trial Now

Confusing about what to choose? Our team will schedule a demo shortly.