Cancer

Question 1

What are oncogenes?

Answer 1

Genes that have mutated to ones that cause cancer.

Question 1

What are tumours caused by?

Answer 1

Uncontrolled mitosis

Question 1

How does the body prevent growth of tumours?

Answer 1

Mutations in cells are detected and therefore undergo programmed cell death before the cell can divide and cause a tumour.

Question 2

What happens if cells containing oncogenes are not destroyed?

Answer 2

They undergo programmed cell death.

Question 3

What are carcinogens?

Answer 3

Agents that cause cancer, such as UV, tar in tobacco and xrays.

Question 4

What do tumour suppressor genes code for?

Answer 4

Genes that code for proteins that regulate the cell cycle.

Question 5

Name 3 functions that cells containing tumour suppressor genes do.

Answer 5

DNA repair
Slowing the cell cycle
Apoptosis

Question 6

What do tumour suppressor genes do for cells?

Answer 6

They ensure that cells containing mutated DNA do not replicate.

Question 7

What will happen if tumour suppressor genes are mutated or silenced?

Answer 7

Tumours will develop.

Question 8

How could hypermethylation of DNA lead to tumour development?

Answer 8

Hypermethylation could lead to transcription inhibiting proteins to bind to DNA. If this occurs around tumour surpessor genes then this could result in tumour development.

Question 9

What can mutation of oncogenes produce that could influence speed of the cell cycle?

Answer 9

Mutation could produce proteins that have the ability to speed up the cell cycle.

Question 10

Name the 2 genes that control cell division.

Answer 10

Protooncogenes
Tumour suppressor genes

Question 11

In normal cell division, how can binding of growth factors lead to DNA replication?

Answer 11

Growth factors bind to receptors in the cell surface membrane, which triggers a cascade of reactions in the cytoplasm. These bind to DNA and switches genes on for replication.

Question 12

Name 2 chromosome mutations that can lead to production of oncogenes from protooncogenes.

Answer 12

Inversion
Translocation

Question 13

What effect can inversion and translocation mutations have when an activating segment of a gene is attached to a protooncogene?

Answer 13

Gene expression may be upregulated.
The protein produced may be unable to be switched off.

Question 14

How does oestrogen regulate transcription?

Answer 14

By stimulating oestrogen receptors,

Question 15

How can high concentrations of oestrogen affect expression of genes?

Answer 15

May result in over expression of the oestrogen gene.

Question 16

How can high oestrogen concentrations lead to breast tumours?

Answer 16

Breast tumour cells rely on oestrogen to stimulate expression of cell cycle genes that lead to growth and replication.

Question 17

Explain how breast cancer might be treated.

Answer 17

A drug with a similar shape to oestrogen can be used to act as an inhibitor and bind to oestrogen receptor sites before the oestrogen binds.

Question 18

Name 2 things that can happen as a result of a protooncogene becoming an oncogene.

Answer 18

Permanent activation of relay proteins in the cytoplasm
Excessive production of growth factors secreted biology

Question 19

Name 3 ways that mutagenic agents can cause mutations in cells.

Answer 19

Removing groups from nucleotide bases
Adding groups to nucleotides
Producing highly reactive free radicals in cells.

Question 20

Name 3 methods of treating cancer.

Answer 20

Surgery
Radiotherapy
Chemotherapy

Question 21

Name 3 ways that cancer can be prevented.

Answer 21

Avoid exposure to mutagenic agents
Remove healthy tissues before signs of cancer
Genetic screening

Question 22

What is a tumour?

Answer 22

An uncontrolled growth of cells which forms a lump.

Question 23

Explain how tumours can cause harm to the body.

Answer 23

Damaging the organ
Causing blockages
Exerting pressure onto organs

Question 24

What are malignant tumours?

Answer 24

Cancerous tumours that grow rapidly and have the ability to metastasise.

Question 25

What is metastasis?

Answer 25

Where cancer cells break off the original tumour and spread through the blood stream and attach to other parts of the body.

Question 26

What are benign tumours?

Answer 26

Non cancerous, slow growing tumours that do not metastasise.

Question 27

How can benign tumours cause damage?

Answer 27

By exerting pressure onto internal organs

Question 28

Give one way that benign tumours differ from malignant tumours.

Answer 28

Benign tumour cells cannot metastasise.