A protein that binds to the operator and blocks the RNA polymerase

• regulator
• repressor
• activator
• corepressor

The "on/off" switch for an operon is called the

• promoter
• repressor
• operator
• gene

What is the name of the stretch of DNA where RNA polymerase binds?

• operator
• promoter
• enhancer
• origin

What is the role of operons in prokaryote gene expression?

• It makes the genes prokaryotes be turned on
• It accounts for the regulation of gene activity in response to the needs of the cells
• To make DNA for the gene
• To make the gene turn of and off

In the lac operon model the genes within the operon will be expressed if:

• lactose is absent in the cell
• glucose is present in the cell
• lactose is present in the cell

The lac operon genes only become expressed if:

• lactose binds to the repressor
• glucose binds to the repressor
• lactose binds to the operator
• the repressor binds to the operator

The repressor is the protein product of a(n)

• operator

• regulatory gene

• lac gene

• corepressor

lac operon was proposed by

• Meselson and Stahl

• Jacob and Monod

• Hershey and Chase

• Watson and Crick

In the lac operon the inducer is

• allolactose

• glucose

• galactose

• all of the above

what is an operon?

• a part of a ribsome
• a part of a Rna
• a unit made up of linked genes that code for proteins needed to do a specific task
• needed for dna replication