The run-on reaction is usually done in the presence of labeled nucleotides so the products will be labeled.

TLS Online TPP Program

#Id: 6373

#Unit 2. Cellular Organization

The lac mRNA (as most mRNA is in bacteria) is extremely unstable and decays with a half-life of only 3 minutes.

TLS Online TPP Program

#Id: 6374

#Unit 2. Cellular Organization

B-1,6-allolactase is a true inducer of Lac operon which activates Lac ZYA gene expression by inhibiting Lac Repressor

TLS Online TPP Program

#Id: 6375

#Unit 2. Cellular Organization

Molecules that induce enzyme synthesis but are not metabolized are called gratuitous inducers such as IPTG

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#Id: 6376

#Unit 2. Cellular Organization

IPTG (isopropyl b-D-1-thiogalactopyranoside) 

X-gal (5-bromo4-chloro-3-indolyl-b-D-galactopyranoside). When acted on by that enzyme, X-gal releases a blue color that makes it useful as substrate in assays.

TLS Online TPP Program

#Id: 6377

#Unit 2. Cellular Organization

TLS Online TPP Program

#Id: 6378

#Unit 2. Cellular Organization

The lac operon has three paradoxes

if the operon is in a repressed state, how does the inducer enter the cell to start the process of induction

 If the operon is in a repressed state, how Repressor is removed with allolactose 

 How is allolactose synthesized in Repressed state Answer is Leaky Expression