Lac Operon

In the lac operon the inducer is

• allolactose

• glucose

• galactose

• all of the above

The lac operon is an example of an inducible operon. Which of the following describes the process that occurs when lactose is present?

• The lactose binds to the repressor which inactivates it and the repressor binds to the operator to turn translation on.

• The lactose binds to the repressor which activates it and the repressor releases from the operator to turn translation on.

• The lactose binds to the repressor which inactivates it and the repressor releases from the operator to turn translation on.

• The lactose binds to the repressor which activates it and the repressor binds to the operator to turn translation on.

Tags

NGSS.HS-LS3-1

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

• regulator

• repressor

• activator

• corepressor

Operons are found in which of the following organisms?

• Bacteria(prokaryotes)

• plants and animals(eukaryotes)

• only animals

• virsuses

An operon consists of all the the following EXCEPT

• operator

• promoter

• regulatory gene

• genes of the operon

What is 1 in the diagram?

• RNA polymerase

• Inducer

• Repressor

• Operator

What is 4 in the diagram?

• RNA polymerase

• Inducer

• Repressor

• Operator

Match the following genetic regions to their roles:

• Operator

• The on/off switch where the repressor protein binds

• Promotor

• Makes a repressor protein

• Genes of Operon

• Codes for the main protein / enzymes

• Regulatory gene

• Place where transcription begins

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

The lac operon is…

• Inducible operon so starts off and is activated by lactose

• Inducible operon so starts on and is deactivated by lactose

• Repressible operon so starts off and is activated by lactose

• Repressible operon so starts on and is deactivated by lactose