lecture 18 (cancer)

Question 1

cancer cells can:

Answer 1

multiply in the absence of growth factor and resist against signal that induce cell death (apoptosis)

Question 2

Metastasis is:

Answer 2

when the cancer cell invade the surrounding tissues and supplies blood vessel

Question 3

what are some general properties of cancer cell?

Answer 3

• controls the growth signals without exterior help
• insenstive to antigrowth signals
• resist death of cell
• supplies angiogenis (blood vessel to feed)
• limitless in division
• invades tissues (metastasis)

Question 4

where does the cancer cell orginate from?

Answer 4

rapidly dividing cells (proliferating)

Question 5

True or False: it is rare to induce cancer cells in non-dividing cells.

Answer 5

TRUE

Question 6

Mutation in ________ can give rise to cancer

Answer 6

Adult Stem cells

Question 7

what is an example of cancer arised from haematopeiotic stem cell?

Answer 7

leukemia

Question 8

how many types of protein that participate in controlling cell growth and division?

Answer 8

7 types

Question 9

what is proto-oncogen?

Answer 9

A gene involved in normal cell growth that encode proteins that promote cell proliferation

Question 10

True or False: Mutation in one copy of proto-oncogene (1 allele) is not enough to induce cancer cells.

Answer 10

False, it is enough to turn it to oncogene

Question 11

Tumor suppressive gene:

Answer 11

is a gene that encodes proteins that acts to regulate cell division, keeping it in check.

Question 12

care taker genes:

Answer 12

is a type of tumer supresser gene that repair damaged DNA

Question 13

what is the difference between loss of function mutation and gain of function mutation?

Answer 13

Loss-of-function mutations result in an inactive or less active protein (two alleles needs to be mutant), whereas gain-of-function mutations lead to a more active protein or gain of a different function (one allele is enough for mutation).

Question 14

what are the two important region of threatend mutation for cancer?

Answer 14

• growth factor receptor inducing a gain of function mutation leading it to work all the time
• loss of function mutation in E2F a transcripition factors

Question 15

what is the type of mutation that occurs to proto-oncogen to convert them into oncogenes causing cancer?

Answer 15

gain of function mutation

Question 16

what are the four mechanism that can produce oncogens?

Answer 16

1) point mutation in proto-oncogen which result in hyperactive protein production
2) chromosomal translocation of fusion of two gens to produce hybrid protein which is more active
3) chromosomal translocation that puts a diiferent promoter in control of the proto-oncogen which cause high production of proto-oncogens
4) the increase in DNA segemant containing proto-oncogen to increase the production of it (too much alleles)

Question 17

how can viruses cause cancer?

Answer 17

viruses can insert oncogenes by accaccumulating the host gene

Question 18

why can viruses accumulate the host DNA?

Answer 18

because it doesnt have repair enzymes

Question 19

types of protein induced from tumour suppressor genes:

Answer 19

1) Rb: to prevent excessive cell growth by inhibiting cell cycle progression until a cell is ready to divide.
2) p16: slows cell division by slowing the progression of the cell cycle from the G1 phase to the S phase
3) p53: arrest the cell cycle if the DNA is damaged

Question 20

True or False: in tumour supperssive genes one allele mutation is enough to cause cancer asssuming cancer is caused by single mutation.

Answer 20

False, two alleles

Question 21

proteins that promotes apoptosis:

Answer 21

1) caretaker genes ( enzymes that participate in DNA repair)
2) Rb tumor suppressor gene
3) APC gene
4) BRACA-1 (when mutated causes brest cancer)

Question 22

True or False: more than one mutation is needed to develop cancer

Answer 22

true

Question 23

what does a mutation in APC tumour suppressor gene cause?

Answer 23

it makes the gene unstable and cause teh cell to divide and create a mass

Question 24

proteins that are classified as proto-oncogens are:

Answer 24

1) cyclin E
2) E2F
3) receptors

Question 25

what type of mutation is found in tumor suppressor gene??

Answer 25

loss of function mutation

Question 26

function of p53:

Answer 26

it acts as a check point that arrest the cell cycle if DNA is damaged

Question 27

How does mutation in p53 cause cancer?

Answer 27

P53 gene mutations change single amino acids, which impair the protein’s function. cell proliferation is not regulated effectively and DNA damage can accumulate in cells.

Question 28

3T3 is a cell line which has a mutation in:

Answer 28

p53