3.3 - How Development is Controlled

Question 1

How does the lac operon work?

Answer 1

When lactose is present, it binds to the repressor molecule. This means the repressor molecule cannot bind to the operator gene. This means RNA polymerase can bind to the operator gene and mRNA coding for B-glactosidase is made

Question 2

What does acetylation of histone proteins do?

Answer 2

Results in switching genes on by loosening its wrapping around histones

Question 3

What does demethylation of DNA do?

Answer 3

Allow RNA polymerase to bind, switching genes on

Question 4

How does methylation occur?

Answer 4

Methyl group binds to a cytosine that is next to a guanine. This is an epigenetic marker and prevents the binding of RNA polymerase, preventing transcription