cancer genet

Question 1

what are cancer genes

Answer 1

changes in the DNA sequence of key genes, which are known as cancer genes. Therefore all cancers are genetic diseases.

Question 2

factors that cause cancer

Answer 2

environmental- chemicals

exogenous factors- Viruses can introduce their own genes into cells

genetics-genes that make a person more susceptible to cancer can be passed to the next generation

Question 3

Meats cooked at high temperatures

Answer 3

temperatures form chemicals that maycausechanges in your DNA, which maylead to cancer. Eating a large amount of well-done, fried or barbecued meats has been linked to an increased risk of colorectal, pancreatic and prostatecancer.

Question 4

what does poorly diffrentaited mean

Answer 4

High grade
This means that the tumor cells don’t look like normal cells. They’re disorganized under the microscope and tend to grow and spread faster

Question 5

which tumour is well differentiated

Answer 5

benign

Question 6

6 halmarks of cancer

Answer 6

self sufficient in growth signals

insensitivity to anti growth signals

evading apoptosis

limitless replicative potential

sustained angoigenisis

tissue invasion and metastasis

Question 7

define angoigenisis

Answer 7

is the growth of new blood vessels that tumors need to grow.

Question 8

what do germ cells do

Answer 8

produce eggs and s

Question 9

what are teh somatic cells

Answer 9

any cell of a living organism other than the reproductive cells.
]only mitosis

Question 10

are somatic inheritable

Answer 10

no as they don’t affect any gametes or mioesis

Question 11

do germline mutations affect their children

Answer 11

heritable
as the mutaions are in gametes
all the cells affected in the offspring

Question 12

muations is somatic cells

Answer 12

Deletions
Duplications
Inversions
Translocations
Single base substitutions (point mutations – silent, nonsense, missense)

Question 13

cancer genome will always aquire what sort of changes

Answer 13

epigenetics

Question 14

what do they do

Answer 14

alter the chromotin structure and gene expression

Question 15

how are they shown at DNA sequence level

Answer 15

methylation of some cytosine

Question 16

what is Chromosome Instability

Answer 16

higher than normal rate of mis segregation of chromosome or part of chromosome

Question 17

when does it happen and why

Answer 17

during mitosis
defective cell cycle
quality control mechansim

Question 18

3 stages of cancer

Answer 18

initiation, promotion, and progression

Question 19

The firststage of carcinogenesis,

Answer 19

initiation, results from an irreversible genetic alteration, most likely one or more simple mutations, transversions, transitions, and/or small deletions in DNA.

Question 20

Cancer harbours a large number of somatic mutations

Answer 20

Cancer harbours a large number of somatic mutations

Question 21

what does UV radiations do

Answer 21

The DNA damage from UV radiation leads to the formation of covalent bonds between two adjacent pyridimines (C and T) in the DNA molecule

Question 22

what will the dna polymerase do

Answer 22

insert 2 adenine opposite teh dimer

if these occur in critical genes leads do aggresisve cell growth

Question 23

signature of UV radaitaion

Answer 23

c to t transition

Question 24

signature mutation of smoking

Answer 24

g to t transition

Question 25

Driver mutation

Answer 25

have growth advantage and are positively selected during cancer : few mutations can confer a selective advantage and are recurrently found (in homozygote state)

Question 26

oncogenes

Answer 26

cancer genes in which the driver muations are activating or cause new functions

Question 27

tumour suprresors

Answer 27

driver mutations are inactiving the functions

Question 28

passenger mutation

Answer 28

no great advanteg | many mutations can be tolerated by somatic cells (often in heterozygote state)

Question 29

Driver mutations tend to cause

Answer 29

cause clonal expansions

Question 30

do Passenger mutation  cause clonal expansion

Answer 30

a mutation that has no effect on the fitness of a clone but may be associated with a clonal expansion because it occurs in the same genome with a driver mutation. This is known as a hitchhiker in evolutionary biology.

Question 31

hitchhiker

Answer 31

a mutation that has no effect on the fitness of a clone but may be associated with a clonal expansion because it occurs in the same genome with a driver mutation

Question 32

Candidate driver mutations may also be distinguished from passengers

Answer 32

by their tendency to have a greater impact on protein function than passenger mutations do. The functional impact of a mutation may be assessed on the basis of evolutionary conservation

Question 33

how to identify driver mutation

Answer 33

one approach | by assuming driving mutations to be higher in cancer samples that background mutation rate

Question 34

bad

Answer 34

too much variabilty in cancer types, samples of cancer, genomes too mnay false positive calls

Question 35

oncogene

Answer 35

gene with potential to cause cancer

Question 36

what are proto oncogenes

Answer 36

normal genes involved in cell growth and proliferation or inhibition of apoptosis

Question 37

One mutation is sufficient for role in cancer development

Answer 37

(DOMINANT, GAIN OF FUNCTION )

Question 38

what are the 3 mechanism of oncogenes activation

Answer 38

gene subsitution gene amplification chromosome rearrangemnet

Question 39

where does gene amplification occur

Answer 39

redundant part of teh dna that contain critical dosage dependent genes

Question 40

example of a dependent gene

Answer 40

myc

Question 41

what is myc

Answer 41

a potential transcription fator | a proto oncogene

Question 42

a mutation that activate the promoter causes

Answer 42

increase proto oncogene expression

Question 43

function of abl gene

Answer 43

ABL is activated to stimulate cell proliferation or differentiation, survival or death, retraction, or migration

Question 44

what causes it to do its functoin

Answer 44

In response to growth factors, cytokines, cell adhesion, DNA damage, oxidative stress, and other signal

Question 45

what does bcr abl gene cause

Answer 45

elevated tyrosine kinase activity

Question 46

function of ras protien

Answer 46

control cellular signalling pathway responsible for cell proliferation, cell differentiation, cell adhesion, apoptosis, and cell migration.

Question 47

what family does ras gene belong to

Answer 47

GTPase

Question 48

how does ras act

Answer 48

on or off switch

Question 49

what does it control normally

Answer 49

cell proliferation

Question 50

when mutated

Answer 50

cell divides uncontrollably

Question 51

where does the most common mutation take place

Answer 51

g12

Question 52

hoe is the activity of rsa governed

Answer 52

``` binding to gtp (in active state) or gdp (in inactive state) ```

Question 53

how are tumour supressor genes normally caused by loss of function

Answer 53

RECESSIVE

Question 54

2 hit hypothesis

Answer 54

In the first event in the two-hit model is an inherited mutation, however inheriting one germline copy of a damaged gene present in every cell in the body is not sufficient to enable this cancer to develop. A second hit (or loss) to the good copy in the gene pair could occur somatically, producing cancer.

Question 55

prediction from the hypothesis

Answer 55

This hypothesis predicts that the chances for a germline mutation carrier to get a second somatic mutation at any of multiple sites in his/her body cells is much greater than the chances for a non-carrier to get two hits in the same cell.

Question 56

which transcription factor binds does rb bind do

Answer 56

e2f

Question 57

function of p53

Answer 57

DNA repair, inducing apoptosis, transcription, and regulating the cell cycle

Question 58

what gene encodes p53

Answer 58

tp53

Question 59

overall function of p53

Answer 59

bind to dna to regulate gene expression and prevent teh accumilation of mutations

Question 60

BRCA1 production role of dna repair

Answer 60

phosphorylated by ATM and CHK2 in response to double – stranded DNA breaks (i.e. these could be produced due for example by ionizing radiation).

Question 61

function

Answer 61

BRCA1 binds to BRCA2 which interacts with RAD51 to form a complex which is involved in DNA repair

Question 62

loss of rad51 leads to

Answer 62

increased unrepaired dna