Midterm 2 - Notes 4 (Part 1)

Question 1

Why study plant tumours on the molecular level? (3)

Answer 1

1. Understanding the mechanisms underlying cellular differentiation
2. Best studied example of inter-kingdom lateral gene transfer
3. Led to the primary tool for generating genetically modified plants

Question 2

What are tumours defined by?

Answer 2

Their phenotype

- not how they originate

Question 3

Phenotype

Answer 3

The set of observable characteristics of an individual resulting from the interaction of its genotype with the environment

Question 4

Tumour

Answer 4

An abnormal mass of tissue that results from excessive cell division or reduced cell death
- can be benign or malignant

Question 5

Benign

Answer 5

No invasion to nearby tissue or spreading to other parts of the body
- will not invade into nearby tissues and cause harm

Question 6

Malignant

Answer 6

Tendency to invade and destroy nearby tissue and/or spread to other parts of the body (forms metastases)
- can break off and establish itself somewhere else in the body and spread from there

Question 7

Merkel cell tumour

Answer 7

Is a rare malignant tumours of the skin in humans

Question 8

Crown gall tumour

Answer 8

A common tumour of stems and roots on an elm tree

Question 9

How do cancer cells reproduce?

Answer 9

Without any restraints on cell growth, cell division or apoptosis

Question 10

Apoptosis

Answer 10

Programmed cell death

Question 11

How do cancers evolve?

Answer 11

Gradually

Question 12

What do tumours contain? (2)

Answer 12

1. Increase number of somatic mutations

2 Epigenetic alterations

Question 13

What does the cause of malfunctioning of regulatory proteins lead to? (2)

Answer 13

1. Increase in cell division

2. Decrease in cell death

Question 14

What are 4 key roles that mutated genes play in?

Answer 14

1. DNA repair
2. Cell signalling
3. Cell growth and differentiation
4. Cell cycle count

Question 15

With check point is environmentally favoured?

Answer 15

G1 to S checkpoint

Question 16

Which check point is all DNA replicated and is environmentally favoured?

Answer 16

G2 to M checkpoint

Question 17

What do mutated genes play a role in? (2)

Answer 17

1. Cell division

2. Apoptosis

Question 18

What do mutated genes help regulate?

Answer 18

The cell cycle

Question 19

At what speed do tumours progress?

Answer 19

Slowly

Question 20

What can increase the chance of getting cancer?

Answer 20

Exposure to mutagen/ carcinogen

Question 21

Can single exposure cause cancer?

Answer 21

No

- needs to be over a long period of time to constant exposure

Question 22

What are the 4 stages in tumour progression?

Answer 22

1. Normal tissue
2. Mild disorder
3. Benign tumour
4. Malignant cancer

Question 23

What increases the chance of getting mutations?

Answer 23

Genetic instability

Question 24

What do pre-cancerous cells do compared to normal cells?

Answer 24

Accumulate more mutations

Question 25

What 3 things may initial mutations interfere with?

Answer 25

1. DNA repair
2. DNA damage response
3. Epigenetic control mechanisms

Question 26

What are critical cancer genes necessary to?

Answer 26

Withstand homeostasis

Question 27

What do additional mutations required can cause the cell to do? (3)

Answer 27

1. Constitutively activate cell division in absence of growth factors
2. Become insensitive to external and internal signals
3. Induce help from normal tissues

Question 28

What are 4 examples of external and internal signals?

Answer 28

1. Anti-proliferating factors
2. Apoptosis inducing factors
3. Factors inducing differentiation
4. Factors preventing proliferation without adhesion

Question 29

What can subsequent mutations become?

Answer 29

Invasive

Question 30

Oncogene

Answer 30

Cancer causing gene

- only when mutated

Question 31

What is an example of a GOF gene?

Answer 31

Oncogene

• dominant
• over activation/over expression

Question 32

What is an example of LOF gene?

Answer 32

Tumor supressor genes

• recessive
• under activate/ missing