cellular control

Question 1

What is programmed cell death known as?

Answer 1

Apoptosis.

Question 2

Distinguish between terms regulatory gene and structural gene.

Answer 2

Regulatory genes produce a regulatory protein/ transcription factor, whereas structural genes produces enzymes.

Question 3

Describe how genes Z, Y are switched on in bacteria that are moved to a nutrient medium that contains lactose.

Answer 3

• When lactose is present it binds to the regulatory protein.
• This changes the shape of the regulatory protein, so lactose cannot join not operator region and can not block RNA polymerase from joining the promoter region. So RNA polymerase does join the promoter region and moves along during transcription.
• Causing structural genes produce to be expressed.

Question 4

When no lactose is present.

Answer 4

-Repressor protein binds to the operator region and partially covers the promoter region.
-RNA polymerase cant bind to promoter so Z and Y can’t be transcribed.

Question 5

When lactose is present.

Answer 5

• It acts as an inducer.
• Lactose binds to the repressor to protein, stopping it from binding to the operator region.
• Therefore, RNA polymerase cant bind to promoter region and transcribe Z and Y.