3.8.2.3 Gene Expression and Cancer

Question 1

What is cancer?

Answer 1

Uncontrolled cell division

Question 2

Which genes are responsible for controlling the rate of cell division?

Answer 2

Oncogenes and tumour-suppressor genes

Question 3

Where do oncogenes come from?

Answer 3

They normally derive from proto-oncogenes

Question 4

What is the purpose of proto-oncogenes?

Answer 4

They normally code for proteins that regulate cell growth by providing protein signals that cause cell division or by regulating cell apoptosis (cell death)

Question 5

What types of proteins does proto-oncogene involvement occur in?

Answer 5

All kinds

Question 6

How is a proto-oncogene turned into an oncogene?

Answer 6

A mutation

Question 7

What is the role of tumour-suppressor genes?

Answer 7

They produce proteins that slow down cell division

Question 8

What occurs when a mutation occurs in a tumour-suppressor gene?

Answer 8

It stops proteins that slow down division from being formed

This is called silenced

Question 9

What genes are affected by epigenetics?

Answer 9

Tumour-suppressor genes

Question 10

Which hormone falls after menopause?

Answer 10

Oestrogen

Question 11

How is Oestrogen and breast cancer linked?

Answer 11

By positive feedback
In breast tissue, fat cells produce more Oestrogen
Breast cancer tumours produce more Oestrogen

Question 12

What is the process of Oestrogen affecting DNA synthesis?

Answer 12

Oestrogen diffuses across the cell membrane (lipid soluble)
Oestrogen binds to a complimentary transcriptional factor
The transcriptional factor is caused to change shape
The DNA binding site can now bind to DNA (activated)
Transcriptional factor moves through a nuclear pore to bind to DNA bases
This stimulates the transcription of a gene