Gene Regulation

What is an operon ?

A group of genes under the control of a single promoter (operator)

Which of the following conditions would cause transcription to be activated

A repressor protein deactivated by an inducer

How can DNA methylation affect transcription ?

It may prevent the binding of regulatory transcription factors

On its chromosome , an E coli cell is lac I (-) , lac Z (+), lac Y (+) and lac A (+) . It has an F factor that is lac I (+) , lac Z (+), lac Y (+) and lac A (+). What is the expected level of expression of the lac operon genes ( lac Z (+), lac Y (+) and lac A (+) ) in the absence of lactose?

Neither lac operon would be expressed

Operons involved with the biosynthesis of molecules such as amino acids, are most likely to be regulated in the following manner :

The product of bio synthetic pathway represses transcription

What is an advantage of alternative splicing ?

The same gene can encode multiple proteins

When the lactose repressor is bound to the lactose operon

access to the promoter by RNA polymerase is blocked and transcription of the operon does not occur

The binding of _____ to the lac repressor can cause the lac repressor to ______ to the operator site and thereby _______ transcription

allolactose: not bind: increases

When tryptophan binds to the trp repressor , this causes the trp repressor to _____ to the trp operator and ____ transcription.

bind: inhibit

According to the histone code hypothesis, the pattern of histone modifications acts like a language that...

influences chromatin structure

A repressor is a _______ that ______ transcription

regulatory protein: inhibits

The process of RNA interference may lead to

the degradation of an mRNA and therefore the inhibition of translation