Tumours

Question 1

What are the 2 types of tumours?

Answer 1

Benign and malignant

Question 2

What is a tumour?

Answer 2

A group of abnormal cells which form lumps or growths

Question 3

Is malignant cancerous?

Answer 3

Yes

Question 4

Is benign cancerous?

Answer 4

no
Non-cancerous

Question 5

Removal of malignant tumours?

Answer 5

Usually involves radiotherapy and/or chemotherapy as well as surgery

Question 6

Removal of benign tumours?

Answer 6

Can usually be removed by surgery alone

Question 7

Malignant tumours growth?

Answer 7

Grow rapidly

Question 8

Benign tumours growth?

Answer 8

Grow very slowly

Question 9

What is metastasis?

Answer 9

Cells can break off these tumours and spread to other parts of the body through the blood stream or lymphatic system

Question 10

What does metastasis lead to?

Answer 10

The spread of tumours to other places in the body, affecting multiple organs

Question 11

Do benign tumours metastise?

Answer 11

No

Question 12

What does cancer arise from?

Answer 12

Uncontrolled mitosis due to mutations in genes regulating the cell cycle
The mutations are for example, early cell death or the cell being destroyed by the body’s immune system

Question 13

Do cancer cells need growth factors to grow?

Answer 13

No- they grow with or without growth factors `

Question 14

What are the 2 types of genes involved with tumours?

Answer 14

Tumour suppressor genes
Proto-oncogenes

Question 15

What are tumour suppressor genes?

Answer 15

Normal genes which encode proteins that:
-repair DNA
- slow the cell cycle at check points
- signal apoptosis if damage is irreparable

Question 16

How many copies of the tumour suppressor genes?

Answer 16

2 copies and both need to be silenced

Question 17

What can mutations or epigenetic silencing of tumour suppressor genes lead to?

Answer 17

Tumour formation

Question 18

How many copies of oncogenes?

Answer 18

Only one- just need to switch one on

Question 19

What do proto-oncogenes code for?

Answer 19

Proteins that stimulate cell growth and differentiation

Question 20

What can mutations due to carcinogens convert pro-oncogenes into?

Answer 20

Oncogenes- causes constant activation of proteins which stimulates cell growth and division- speeds up the cell cycle

Question 21

How can oncogene activation occur?

Answer 21

Via the inversion of translocation mutations on a proto-oncogene leading to:
- increased gene expression
- protein production cannot be switched off

Question 22

What does increased methylation of tumour suppressors genes do?

Answer 22

Silences the genes as transcription factors are unable to bind
Tumour suppressor genes are therefore not synthesised so tumour formation occurs

Question 23

Reduced methylation of proto-oncogenes leads to increased or decreased expression of the gene?

Answer 23

Increased expression as the gene becomes accessible
Transcription factors then bind and protein synthesis is activated
The gene behaves like an oncogene, even without a mutation

Question 24

What impacts tumour suppressor genes?

Answer 24

Increased methylation and decreased acetylation

Question 25

What impacts protooncogenes?

Answer 25

Decreased methylation Increased acetylation

Question 26

How does increased methylation impact tumour suppressor genes?

Answer 26

Transcription factor cant bind to promoter region- inhibit transcription Gene expression = switched off Leads to uncontrolled cell division- leading to tumours

Question 27

How does decreased acetylation lead to impacts on tumour suppressor genes?

Answer 27

Chromatin becomes more tightly coiled Transcription factor cant bind to the promoter region- inhibits transcription Gene expression = switched off Leads to uncontrolled cell division- leading to tumours

Question 28

How does decreased methylation impact protooncogenes?

Answer 28

Over stimulate transcription Uncontrolled cell vision- tumour formation

Question 29

How does increased acetylation impact protooncogenes?

Answer 29

Chromatin less tightly coiled Overstimulation of transcription- uncontrollable cell division- leads to tumour formation