7.2 Cancer

Question 1

Tumour def

Answer 1

A mass of abnormally growing cells

Question 2

Benign tumour def

Answer 2

Growths of abnormal cells that are contained in once area, usually within a membrane, and do not invade other tissues

Question 3

Malignant tumour def

Answer 3

Invade neighbouring tissues and spread to different parts of the body in blood where they form secondary tumours. They are also known as cancers

Question 4

Cancer def

Answer 4

uncontrolled growth and division

Question 5

Can tumours be caused by communicable diseases?

Answer 5

Yes. Eg:
- agrobacterium tumefaciens can cause crown gall in plants
- human papilloma virus (HPV) can cause cervical cancer in humans

Question 6

What effect to benign tumours have on the body

Answer 6

• they grow large and affect the tissue around it
• if it causes pressure or damage to an organ, it can be life-threatening
• eg benign tumours on the brain can be dangerous because there is no extra space for them to grow into

Question 7

What effect do malignant tumours have on the body

Answer 7

• initial tumour may split up, releasing small clumps of cells into the bloodstream or lymphatic system
• carried to different parts of the body where they may lodge in another organ
• they continue uncontrolled division and form secondary tumours
  they break up and circulate in the blood stream and disrupt normal tissues

Question 8

Do cancer cells work differently to normal cells

Answer 8

Yes, they divide more rapidly and live longer

Question 9

What happens if a malignant tumour is left untreated

Answer 9

• growing tumour completely disrupts normal tissues and will often kill the person
• because of the way malignant tumours spread, it can be difficult to treat

Question 10

What are some causes of cancer

Answer 10

• genetic risk factors
• chemicals in tobacco can cause mutations that trigger the formation of tumours
• ionising radiation (UV light and X-rays) can interrupt the normal cell cycle and cause tumours to form
• virus infections

Question 11

Suggest and explain several factors that might cause tumours to develop

Answer 11

• ionising radiation: can damage genetic material
• chemicals eg asbestos and tar: can cause mutations
• viruses damage DNA

Question 12

What are the two main ways to treat cancer

Answer 12

• radiotherapy: when cancer cells are destroyed by targeted doses of radiation
• chemotherapy: where chemicals are used to stop the cancer cells dividing or making them ‘self-destruct’

Question 13

Risks and benefits of radiotherapy

Answer 13

• risks:cell damage to healthy cells around the tumour
• benefits: reduces size of tumour

Question 14

Risks and benefits of chemotherapy

Answer 14

• risks: damages all dividing cells
• benefits: stops the tumour growing and destroys the tumour