20.5 & 20.6: Gene expression & cancer & genome projects

Question 1

Types of tumour

2

Answer 1

benign

malignant

Question 2

Benign tumour

Answer 2

non - cancerous

Question 3

Malignant tumour

Answer 3

cancerous

Question 4

Benign tumour

growth rate and size

Answer 4

grow very slowly and can grow to a large size

Question 5

Malignant tumour

growth rate and size

Answer 5

grow rapidly and can grow to a large size

Question 6

Cell nucleus in a benign tumour

Answer 6

Relatively normal appearance

Question 7

Cell nucleus in a malignant tumour

Answer 7

Often larger and appear darker due to an abundance of DNA

Question 8

Benign tumour cells

Answer 8

Differentiated and produce adhesion molecules which makes them stick together and remain in the tissues from which they arise.

Question 9

Malignant tumour cells

Answer 9

Become de-differentiated and don’t produce adhesion molecules

Question 10

Metastasis

Answer 10

Forming of secondary tumours

Question 11

Characteristics of a benign tumour

Answer 11

surrounded by a capsule and remain as a compact structure

Question 12

Characteristics of a malignant tumour

Answer 12

not surrounded by a capsule and have finger like projections that can grow into the surrounding tissue

Question 13

Effects of malignant tumour

Answer 13

often systemic effects such as weight loss and disease

Question 14

Systemic

Answer 14

whole body

Question 15

Treatment of malignant tumours

Answer 15

usually involves chemotherapy, radiotherapy and surgery

and more frequently reoccur after treatment

Question 16

Treatment of benign tumours

Answer 16

surgery

Question 17

Oncogenes

Answer 17

Mutations of proto-oncogenes

Question 18

Protooncogenes

Answer 18

Stimulate a cell to divide when growth factors attach to a protein receptor on its cell-surface membrane. Which activates genes that cause DNA replication an cell division.

Question 19

Reasons why the mutation of a protooncogene into an oncogene can permanently activate an oncogene
2

Answer 19

• Receptor protein on the cell surface membrane can be permanently activated so cell division occurs even without growth factors
• The oncogene may code for a growth factor that is produced in excessive amounts, again stimulating excessive cell division

Question 20

Tumour suppressor genes

Answer 20

Slow down cell division, repair mistakes in DNA and trigger apoptosis.

Question 21

Tumour suppressor genes mutation

Answer 21

switches it off/ inactivates it
stops inhibiting cell division
cells can grow out of control

Question 22

Most cancers are

Answer 22

acquired not inherited

Question 23

Hypermethylation

Answer 23

Increased methylation

Question 24

Hypomethylation

Answer 24

Reduced methylation

Question 25

Process by which hypermethylation may lead to cancer

Answer 25

Occurs in a specific region of tumour suppressor genes.
Leads to the tumour suppressor gene being inactivated.
Leads to increased cell division and formation of a tumour.

Question 26

Oestrogen concentrations and breast cancer

Answer 26

Fat cells in breasts tend to produce more oestrogen after menopause. Oestrogen causes proto-oncogenes in breast tissue to develop into oncogenes which leads to development of a tumour.