# GATE2012-53

$\text{Statement for Linked Answer Questions 52 and 53:}$

An E $coli$ cell of volume $10^{-12}$ $cm^3$ contains 60 molecules of lac-repressor. The repressor has a binding affinity (${K_d}$) of $10^{-8}$ M and $10^{-9}$ M with and without lactose respectively, in the medium

Therefore the lac-operon is

1. repressed and can only be induced with lactose
2. repressed and cannot be induced with lactose
3. not repressed
4. expressed only when glucose and lactose are present
in Others
edited