Catabolite Repression

Question 1

What is the name of the mechanism when a cell has a choice between two different energy sources (e.g. glucose & lactose)?

Answer 1

Catabolite Repression

Question 2

What causes Catabolite Repression?

Answer 2

Low levels of cAMP in the cell

In the presence of glucose, cells make less cAMP

Question 3

What is the complex required for catabolite repression?

Answer 3

cAMP + CAP protein

CAP = Catabolite Activator Protein

Question 4

How does the presence of glucose affect the cAMP + CAP protein complex?

Answer 4

• Glucose IS present then LOW cAMP concentration and complex is NOT formed
• Glucose is NOT present then HIGH cAMP concentration and complex IS formed

Question 5

Is the lac operon subject to dual control?

Answer 5

Yes.
Gene Induction & Catabolite Repression

Question 6

What type of growth can Catabolite Repression lead to in bacteria?

Answer 6

Diauxic Growth

When growth media contain both glucose & lactose

Question 7

What is Global Control?

Answer 7

A regulatory mechanism responding to environmental signal by controlling expression of many different genes

Catabolite Repression is an example of Global Control

Question 8

What is Global Control?

Answer 8

A regulatory mechanism responding to environmental signal by controlling expression of many different genes

Catabolite Repression is an example of Global Control