DNA and cells - CANCER

Question 1

What is a carcinogen?

Answer 1

A cancer inducing agent

Question 2

What is apoptosis?

Answer 2

Programmed cell death (when the cell has irreparable damage it self destructs)

Question 3

What is a mutation?

Answer 3

A change in the DNA sequence

Question 4

What is a tumour?

Answer 4

Abnormal growth of tissue

Question 5

What is cancer?

Answer 5

• When cells in a specific part of the body grow and reproduce uncontrollably
• The cancerous cells can invade and destroy surrounding healthy tissue, including organs

Question 6

What is metastasis?

Answer 6

The process when tumour cells invade other tissues, forming secondary cancers throughout the body

Question 7

Name 3 examples of carcinogens

Answer 7

• Tar (in tobacco)
• UV light
• Asbestos

Question 8

What are oncogenes?

Answer 8

Mutated genes that form due to carcinogens, that has potential to cause cancer

Question 9

What are benign tumours?

Answer 9

• Non cancerous
• Contain abnormal cells surrounded by a connective tissue capsule

Question 10

What is a malignant tumour?

Answer 10

• Cancerous
• Contains a clump of cancer cells

Question 11

What is p53?

Answer 11

A significant tumour suppression gene

Question 12

What does p53 do?

Answer 12

• Detects damaged DNA
• Inhibits progression to S phase
• Activates DNA repair enzymes
• If DNA cannot be repaired, apoptosis is triggered

Question 13

What happens if the p53 gene mutates?

Answer 13

• Cell cycle continues
• Cells can become cancerous

Question 14

How do mutations lead to cancer?

Answer 14

The mutations accumulate - leading to more abnormal growth and metastasis

Question 15

How do we treat cancer?

Answer 15

By blocking some part of the cell cycle

Question 16

What happens if we disrupt the cell cycle?

Answer 16

Cell division (and therefore cancer growth) stops

Question 17

How do drugs used to treat cancer disrupt the cell cycle?

Answer 17

• Prevent DNA from replicating
• Interfere with spindle formation; therefore inhibiting metaphase

Question 18

Why are cancer cells more greatly affected by these drugs than normal cells?

Answer 18

Cancer cells have a very rapid rate of cell division; hence cancer cells are damaged to a greater extent than normal cells

Question 19

Give two differences between the effect of drugs on cancer cells compared with healthy cells throughout the treatment (PPQ)

Answer 19

• Healthy cell number recovers (increases) much quicker
• Cancer cell numbers don’t increase as much

Question 20

Why do chemotherapy drugs have to be given a number of times if they are to be effective in treating cancer?

Answer 20

Cancer cell numbers increase after each dose is complete, so treatment needs to occur again

Question 21

Mikanolide is a drug that inhibits the enzyme DNA polymerase. Explain why this drug may be effective against some types of cancer (PPQ)

Answer 21

• Mikanolide slows DNA replication
• A new strand of DNA is not formed

Question 22

If the DNA of the cell is damaged, a protein called p53 stops the cell cycle. Mutation in the gene for p53 could cause cancer to develop. Explain how (PPQ)

Answer 22

• The cell with faulty DNA continues to divide
• Uncontrolled division produces cancer