Cells and molecular biology of cancer

Question 1

tumour=

Answer 1

abnormal growth of tissue that usually forms a mass

Question 2

what is the cause of all cancer

Answer 2

genetic mutations

Question 3

when do tumours arise

Answer 3

when balance between cell division and cell differentiation or death is disrupted

Question 4

what cells do genetic mutations causing cancer have to be in

Answer 4

proliferating cells

Question 5

what gene mutations are in most tumours

Answer 5

genes controlling cell cycle

Question 6

5 stages of cell cycle

Answer 6

M
G0 
G1
S
G2

Question 7

interphase=

Answer 7

G1, G2, S (synthesis)

Question 8

Gap 1 (G1)=

Answer 8

no visible changes but increase in cell contents (organelles, proteins ect)

Question 9

Synthesis=

Answer 9

replication of DNA occurs, resulting in chromosomes becoming 2 sister chromatids

Question 10

G2=

Answer 10

preparation for division process

Question 11

g0=

Answer 11

not going through cell cycle

Question 12

what ensures the cell cycle is happening in the right order

Answer 12

cyclin- CDK

Question 13

what does cyclin- CDK do

Answer 13

signal stages of the cell cycle to happen

Question 14

what controls cell cycle progression

Answer 14

transition points

Question 15

what halts the cell cycle if the cell is unsuitable

Answer 15

checkpoint pathways

Question 16

when is cyclin level highest in the cell

Answer 16

in mitosis

Question 17

restriction point at_______

Answer 17

G1–> S

Question 18

3 checkpoints in cell cycle

Answer 18

• DNA damage checkpoint
• DNA replication checkpoint
• Mitotic spindle checkpoint

Question 19

what causes external signalling

Answer 19

growth factors

Question 20

internal signalling for the cell cycle can happen because of

Answer 20

DNA damage

Question 21

p53=

Answer 21

transcription factor

Question 22

what 2 proteins have a kinase activity and activate DNA repair and p53

Answer 22

ATM and ATR

Question 23

what happens to p53 after DNA damage

Answer 23

phosphorylation by ATM making p53 go into the nucleus and stimulate expression of many genes including p21

Question 24

what does p21 do

Answer 24

an inhibitor of cyclin and CDK leading to cell-cycle arrest

Question 25

what do most proto-oncogenes code for

Answer 25

components of the regulatory pathways of growth/ cell division

Question 26

how many mutations can enable oncogenes

Answer 26

1- mutation in one allele

Question 27

how many mutations in tumour suppressors genes to inactivate them

Answer 27

2- mutations in both alleles

Question 28

5 types of gene mutation

Answer 28

1. point mutation 2. gene amplification 3. chromosomal translocation 4. local DNA re-arrangement 5. insetional mutagenesis

Question 29

2 main classes of tumour suppressor genes

Answer 29

caretakers and gatekeepers

Question 30

e.g of 2 gatekeepers

Answer 30

Rb | p53

Question 31

what does Rb control

Answer 31

G1--->S restriction point

Question 32

loss of gatekeeper causes

Answer 32

excessive cell proliferation

Question 33

caretakers--->

Answer 33

maintain genetic stability (e.gDNA repair) but not directly involved in controlling cell proiliferation

Question 34

e.g of caretaker

Answer 34

BRCA1 and 2

Question 35

when a cell detects DNA damage levels of what normally increase

Answer 35

p53

Question 36

where does p21 arrest the cell cycle

Answer 36

G1

Question 37

if there is no p53 what happens

Answer 37

cell will carry on the cell cycle even with DNA damages

Question 38

what instructs the DNA repair proteins to start repairing

Answer 38

ATM

Question 39

what usually keeps p53 at low levels

Answer 39

because its bound to Mdm2 which keeps its levels low via degradation

Question 40

what does Rb regulate

Answer 40

a transcription factor (keeping it away from the nucleus) which would otherwise start the expression of genes making the cell progress into the G1 phase

Question 41

what happens in tumours without Rb

Answer 41

transcription factor is always free to bind the DNA---> lots of proliferation

Question 42

what does viral factor E7 produced from HPV do

Answer 42

E7 binds to Rb and keeps it away from the transcription factor

Question 43

what does viral factor E6 produced from HPV do

Answer 43

sequesters p53 so it can no longer stop the cell cycle when DNA needs repair