Topic 8 - 3 - Cancer

Question 1

What is an acquired mutations?

Answer 1

A mutation you develop during your lifetime

Question 2

What is a tumour?

Answer 2

A mass of abnormal cells

Question 3

How are tumours formed?

Answer 3

When a mutation occurs in the genes that control the rate of cell division, it can cause uncontrolled cell division which will then lead to a tumour

Question 4

What is cancer?

Answer 4

Tumours that invade and destroy surrounding tissue

Question 5

What are the two types of gene that control cell division?

Answer 5

1 - Tumour suppressor genes

2 - Proto-oncogenes

Question 6

When functioning normally, how do tumour suppressor genes work?

Answer 6

They slow down cell division by producing proteins that stop cells dividing or cause them to self destruct (apoptosis)

Question 7

What happens if a mutation occurs in a tumour suppressor gene?

Answer 7

The gene will be inactivated. The protein it codes for isn’t produced and the cells divide uncontrollably, resulting in a tumour

Question 8

When functioning normally, how do photo-oncogenes work?

Answer 8

They stimulate cell division by producing proteins that make cells divide

Question 9

What happens if a mutation occurs in a proto-oncogene?

Answer 9

The gene will become overactive, and this stimulates the cells to divide uncontrollably, which results in a tumour.

Question 10

What is an oncogene?

Answer 10

A mutated photo-oncogene

Question 11

What is apoptosis?

Answer 11

A type of programmed cell death. Cells that are infected, damaged or have reached the end of their fictional lives are destroyed

Question 12

Describe a malignant tumour

Answer 12

• Are Cancerous
• Grow rapidly
• Invade and destroy surrounding tissues
• Cells can break off the tumours and spread to other parts of the body in the bloodstream or lymphatic system

Question 13

Describe a benign tumour

Answer 13

• Not cancerous
• Grow slowly
• Covered in fibrous tissue that stops cells invading other tissues
• Often harmless but can cause blockages and put pressure on organs
• Some tumours can become malignant

Question 14

Describe 3 ways in which tumour cells may differ from normal cells

Answer 14

• Larger nucleus
• Sometimes more than one nucleus
• Irregular shape
• Dont produce proteins needed to function correctly
• Have different antigens on their surface
• Dont respond to growth regulating processes
• Divide more frequently

Question 15

What is methylation?

Answer 15

Adding a methyl group onto something

Question 16

Why is methylation of DNA an important method of regulation gene expression?

Answer 16

It controls whether or nit a gene is transcribed and translated. It plays a key role in many processes in the body

Question 17

What is hypermethylation?

Answer 17

When methylation happens too much

Question 18

What is hypomethylation?

Answer 18

When methylation happens too little

Question 19

What is the problem when abnormal methylation occurs?

Answer 19

It can cause the growth of anger related genes

Question 20

Describe one way oestrogen is thought to contribute to the development of some breast cancers

Answer 20

1 - Can stimulate certain breast cells to divide and replicate. This naturally increases the chances of mutations occurring and so increases the chances of cells becoming cancerous
2 - This could also mean that if cells do become cancerous, the rapid replication of the cells can be assisted by the oestrogen
3 - Other research suggests that oestrogen is able to introduce mutations directly to the DNA of certain breast cells, increasing the chances of becoming cancerous