L04 - TUMOUR SUPRESSOR AND ONCOGENES

Question 1

What is the restriction point in the cell cycle?

Answer 1

It occurs after G1 and is where the cell decides whether or not it will divide based on the extra cellular environment e.g is there enough growth factor and nutrients

Question 2

What is retinoblastoma protein (pRB)?

Answer 2

The protein that regulates the restriction point

Question 3

Explain the pRB mechanism of action (4)

Answer 3

• Normally pRB binds to TF
• TF needed for cell to progress into the cell cycle
• When GF is present, cyclin-cdks are activated and inhibits the pRB
• This results in pRB detaching from the TF and the cell can progress into the cell cycle

Question 4

What type of protein is pRB?

Answer 4

Tumour supressor protein

Question 5

Which protein regulates the G1/S checkpoint?

Answer 5

P53