Ch. 8 - Cancer

Question 1

What is cancer?

Answer 1

• disease of the cell cycle where cancer cells don’t heed the normal signals that regulate the cycle
• divide excessively and may invade other tissues of the body

Question 2

Cell cycle control system (3)

Answer 2

• function to trigger and coordinate events of the cycle
• there are critical points (checkpoints), where stop and go signals regulate the cycle
• the default at these checkpoints is to stop unless a “go-ahead” signal (via protein) is given

Question 3

Three primary checkpoints within cell cycle

Answer 3

Occur at G1, G2, and metaphase

Question 4

Cells stop what they’re doing at the red and white bars and will receive signals to continue if (2)

Answer 4

• all key processes up to that point have been completed

- if they receive a message from outside of the cell that indicated that they should (such as a growth factor)

Question 5

G0 phase

Answer 5

-when a cell doesn’t continue to divide but stops at G1 indefinitely, unless damage occurs or they receive a signal from a growth factor to continue to divide

Question 6

Growth factor (2)

Answer 6

• binds to a receptor protein at the surface of the cell

- which starts a signal transduction pathway to the next protein until it reaches the cell control system

Question 7

Benign tumour (2)

Answer 7

• abnormally growing cells remain at the site but don’t spread to other parts of the body
• can still cause problems, especially if they occur in the brain

Question 8

Tumour

Answer 8

An abnormally growing mass of body cells

Question 9

Malignant tumours (3)

Answer 9

• Those that can spread from their original site and can also secrete signal molecules that cause blood vessels to grow towards them
• hijacks your system of O2 and nutrients to fuel their own growth
• if you have this you have cancer

Question 10

Metastasis

Answer 10

Spread of cancer cells beyond their original site

Question 11

Cancer is grouped into 4 main categories

Answer 11

• carcinomas: originate in the external covering of the body (skin) or internal lining of the body (lining of intestine)
• sarcomas: arise in tissues that support the body such as bone, muscle, cartilage, etc
• leukaemia and lymphomas: are cancers of the blood-forming tissues such as bone marrow, spleen and lymph nodes

Question 12

Oncogene

Answer 12

Single gene that causes a normal cell to become cancerous

Question 13

Proto-ongene (2)

Answer 13

• Normal gene that has the potential to become an oncogene

- code for proteins that stimulate cell division or those that suppress cell growth

Question 14

How can a cell acquire an oncogene

Answer 14

From a virus (HPV, Hep B, H. Pylori) or from mutation of one of its own genes

Question 15

How does a cell become cancerous (2)

Answer 15

• require 4+ mutations and take a long time to develop

- multiple changes must occur at the DNA level for a cell to become fully cancerous

Question 16

3 types of tumours

Answer 16

• benign: non-cancerous, stay in one place, don’t spread, don’t usually come back once removed
• precancerous: may develop into cancer if not treated or not normal
• cancerous: cells have grown into nearby tissue and may produce cells that can break away and travel through the blood or lymphatic system

Question 17

Precancerous: hyperplasia

Answer 17

Normal looking cells that grow faster than normal. Some may be precancerous, most aren’t