2.2 Cancer

Question 1

What is cancer?

Answer 1

• group of diseases caused by a growth disorder of cells
• it is the result of damage to the genes that regulate mitosis and the cell cycle
• if the cell cannot regulate its growth this could lead to uncontrolled growth and division of cells. These uncontrolled cells form a growth (tumour) which keeps growing

Question 2

Where can tumours develop?

Answer 2

• they can develop in any organ in the body

Question 3

Where a tumours most commonly found?

Answer 3

• most commonly in; lungs, prostate gland (in males), breasts and ovaries (in females), large intestine, stomach, oesophagus and pancreas

Question 4

When do tumours become cancerous?

Answer 4

• if they change from benign to malignant

Question 5

What are the problems with treating cancer?

Answer 5

• using these kinds of drugs also disrupts the cell cycle of normal cells
• however the drugs are more effective against rapidly dividing cells such as cancer cells
• normal body cells that divide rapidly include hair-producing cells which explains hair loss during cancer treatment

Question 6

What are the treatments for cancer?

Answer 6

-often involves killing dividing cells by blocking part of the cell cycle
- drugs used to treat cancer (chemotherapy) usually disrupt the cell cycle by preventing DNA from replicating and inhibiting the metaphase stage of mitosis by interfering with spindle formation

Question 7

What are the properties of malignant tumours?

Answer 7

• grow rapidly
• less compact
• more likely to be life threatening

Question 8

What are the properties of benign tumours?

Answer 8

• grow more slowly
• are more compact
• less likely to be life threatening

Question 9

What happens if the genes controlling cell growth mutate? (Benign vs malignant)

Answer 9

If the genes controlling cell growth mutate the cells will divide uncontrollably, these mutant cells are very different to normal cells in structure and function that most of them die

Question 10

What happens to any surviving mutants? (Benign vs malignant)

Answer 10

Any surviving mutants are able to divide and clone themselves which forms tumours

Question 11

What are tumour suppressor genes?

Answer 11

genes that code for proteins to trigger apoptosis/ slow cell cycle

Question 12

What are proto-oncogenes?

Answer 12

genes that code for proteins to stimulate cell cycle to progress from one stage to the next

Question 13

How can mutation to tumour suppressor genes and proto-oncogenes cause cancer?

Answer 13

• tumour suppressor: no production of a protein needed to slow the cell cycle
• proto-oncogenes: form permanently-activated oncogenes
• disruption to cell cycle -> uncontrolled cell division -> tumour

Question 14

How can cancer treatments control the rate of cell division?

Answer 14

Disrupt the cell cycle:
• prevent DNA replication
• disrupt spindle formation = inhibit metaphase/anaphase