structure of the lac operon

Question 1

what does the lac operon consist of?

Answer 1

• control elements
• 3 structural genes which code for enzymes that catalyse the breakdown & transport of lactose

Question 2

what are the control elements present in the lac operon?

Answer 2

• Catabolite Activator Protein (CAP) binding site
• promoter (lac P)
• operator (lac O)

Question 3

what is the function of the CAP binding site?

Answer 3

• it is the binding site of CAP

Question 4

what is the function of lac P?

Answer 4

• it is the binding site of RNA polymerase to transcribe structural genes

Question 5

what is the function of lac O?

Answer 5

• it is the binding site of the lac repressor protein, which is a product of the regulatory gene

Question 6

what are the 3 structural genes present in the lac operon?

Answer 6

• lac Z
• lac Y
• lac A

Question 7

what is the function of lac Z?

Answer 7

• it codes for β-galactosidase

Question 8

what is the function of β-galactosidase?

Answer 8

• it is an enzyme which hydrolyses lactose into glucose & galactose,
• & cleaves lactose into allolactose

Question 9

what is the function of lac Y?

Answer 9

• it codes for lac permease

Question 10

what is the function of lac permease?

Answer 10

• it is a membrane transport protein for the transport of lactose into the cells

Question 11

what is the function of lac A?

Answer 11

• it codes for β-galactoside transacetylase