What is the normal function of tumour suppressor genes in the cell cycle?

Tumour suppressor genes inhibit cell division, slow the cell cycle, or promote apoptosis, acting as brakes on cell proliferation.

What happens to cell cycle regulation if a proto-oncogene becomes mutated into an oncogene?

The gene becomes overactive or permanently switched on, leading to uncontrolled cell division and potentially cancer.

What happens to cell cycle regulation if a tumour suppressor gene is inactivated by mutation?

The inhibitory control over cell division is lost, allowing cells to divide uncontrollably and potentially form tumours.

Explain why mutations in both proto-oncogenes and tumour suppressor genes can lead to cancer.

Proto-oncogene mutations cause excessive stimulation of cell division, while tumour suppressor gene mutations remove the normal inhibition of division. Both result in uncontrolled cell proliferation characteristic of cancer.

OCR A-Level Biology H420

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Cellular Control

Oncogenes, tumour suppressor genes and cancer

3 things to know
Components 02 and 03

Overview

The normal role of proto-oncogenes and tumour suppressor genes in the cell cycle, and what happens to that control when either one is mutated.

What you need to know

Answer each one before you reveal it.

Your recallNot started

Process

How can gene mutations cause cancer?

Key term

What are tumour suppressor genes?

Process

What is the normal function of proto-oncogenes in the cell cycle?

Questions from this subtopic

Each one with the model answer underneath.

1
What are the two main categories of genes that regulate the cell cycle?
Model answer
Proto-oncogenes and tumour suppressor genes.
2
What is the normal function of proto-oncogenes in the cell cycle?
Model answer
Proto-oncogenes stimulate cell division and promote progression through the cell cycle.
3
What is the normal function of tumour suppressor genes in the cell cycle?
Model answer
Tumour suppressor genes inhibit cell division, slow the cell cycle, or promote apoptosis, acting as brakes on cell proliferation.
4
What happens to cell cycle regulation if a proto-oncogene becomes mutated into an oncogene?
Model answer
The gene becomes overactive or permanently switched on, leading to uncontrolled cell division and potentially cancer.
5
What happens to cell cycle regulation if a tumour suppressor gene is inactivated by mutation?
Model answer
The inhibitory control over cell division is lost, allowing cells to divide uncontrollably and potentially form tumours.
6
Explain why mutations in both proto-oncogenes and tumour suppressor genes can lead to cancer.
Model answer
Proto-oncogene mutations cause excessive stimulation of cell division, while tumour suppressor gene mutations remove the normal inhibition of division. Both result in uncontrolled cell proliferation characteristic of cancer.

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Oncogenes, tumour suppressor genes and cancer

Overview

What you need to know

How can gene mutations cause cancer?

What are tumour suppressor genes?

What is the normal function of proto-oncogenes in the cell cycle?

Questions from this subtopic

What are the two main categories of genes that regulate the cell cycle?

What is the normal function of proto-oncogenes in the cell cycle?

What is the normal function of tumour suppressor genes in the cell cycle?

What happens to cell cycle regulation if a proto-oncogene becomes mutated into an oncogene?

What happens to cell cycle regulation if a tumour suppressor gene is inactivated by mutation?

Explain why mutations in both proto-oncogenes and tumour suppressor genes can lead to cancer.

Other ways to work this

What is inside Levo

The 3-step method, run for you

Cram a whole paper in one sitting

Blank Blitz makes facts automatic

Build It gets the exam shape right

Test It catches misconceptions

Brain Breaks between sessions

Every question in Cellular Control, on a schedule.