3.8.2.3 Gene Expression and Cancer (Unit 8 Gene Expression) Flashcards

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1
Q

Epigenetics has been associated with what type of disease

A

cancer

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2
Q

All tumours are cancerous - true or false?

A

false

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3
Q

What is a tumour?

A

Mass of cell caused by uncontrolled cell division

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4
Q

Cancer is…?

A

abnormal mass of cells that invades neighbouring tissues or can break away forming secondary tumours

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5
Q

Two types of tumours are?

A

benign and malignant

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6
Q

Which tumour is cancerous?

A

malignant

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7
Q

Which tumour does not invade neighbouring cells?

A

benign

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8
Q

How do cancers spread?

A

blood stream or via lymphatic system

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9
Q

Name the two genes that control cell division

A

Proto-oncogenes and tumour suppressor genes

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10
Q

What is the function of a proto-oncogene?

A

stimulate cell division

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11
Q

what is the function of a tumour suppressor gene?

A

slow down cell division

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12
Q

what would happen if there was a mutation in a proto-oncogene?

A

turn into oncogene - uncontrolled cell division

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13
Q

what would happen if there was a mutation in a tumour suppressor gene?

A

uncontrolled cell division

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14
Q

Mutations in genes that control cell division cause…

A

cancer

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15
Q

Which type of tumour grows more slowly?

A

benign

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16
Q

How might tumour cells look compared to normal cells?

A

different shape
larger/darker nucleus
divide more rapidly

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17
Q

what does methylation do to the DNA?

A

adds a methyl group to it

18
Q

In a proto-oncogene what happens to the methylation of the DNA to turn it into a oncogene?

A

hypomethylation (reduced methylation)

19
Q

In a tumour suppressor gene what happens to the methylation of the DNA to cause cells to divide out of control?

A

Increase methylation - turn gene off

20
Q

Which type of tumour grows rapidly?

A

malignant

21
Q

which type of tumour involves using radiotherapy as well as surgery?

A

malignant

22
Q

Which type of tumour remains compact

A

benign

23
Q

which type of tumour grows finger like projections into surrounding tissue?

A

malignant

24
Q

which type of tumour has a capsule?

A

benign

25
Q

what are oncogenes?

A

mutated pro-oncogenes

26
Q

How to proto-oncogenes stimulate cell growth?

A

growth factor binds to receptor stimulating cell division

27
Q

An oncogene can become permanently activated for one of two reasons?

A
  1. oncogene codes for a receptor that is permanently activated
  2. oncogene codes for excessive growth factor
28
Q

How do tumour suppressor genes work?

A

they slow down cell division, repair DNA or tell cells to die

29
Q

what does apoptosis mean?

A

programmed cell death

30
Q

Which gene regulates cell division and prevents formation of tumours?

A

Tumour Suppressor Gene

31
Q

if a tumour suppressor gene is mutated what is the consequence?

A

stops inhibiting cell division and cells divide out of control

32
Q

mutation in a proto-oncogene leads to

A

oncogenes being activated - uncontrolled cell division

33
Q

mutation in a tumour suppressor gene leads to

A

Tumour suppressor gene being inactivated - uncontrolled cell division

34
Q

abnormal methylation is common in many tumours - what effect can this have on a tumour suppressor gene?

A

hypermethylation of a tumour suppressor gene - inactivity - uncontrolled cell division (p53 not made)

35
Q

what is hypermethylation?

A

addition on methyl groups on DNA - switching off gene expression

36
Q

transcription of genes is controlled by protein molecules called?

A

transcription factors

37
Q

How would methylation of a tumour suppressor gene lead to cancer?

A
  1. Methylation prevents transcription of gene;turns off gene expression
  2. Protein (p53) not produced that prevents cell division/ causes cell death/apoptosis;
  3. No control of mitosis; uncontrolled cell growth due to mitosis
38
Q

Describe how alterations to tumour suppressor gene can lead to development of tumours

A
  1. increased methylation of tumour suppressor gene
  2. mutations in tumour suppressor gene
  3. tumour suppressor gene not expressed
  4. Leading to rapid uncontrolled cell division
39
Q

Which cancer gene would be inhibited due to increased methylation?

A

tumour suppressor gene (TSG) - gene not transcribed!

40
Q

give one way benign tumours differ from malignant tumours

A

Cells of benign tumours cannot spread to other parts of the body/metastasise
OR
Cells of benign tumours cannot invade neighbouring tissues;