topic 8 cancer

Question 1

what can mutations in genes cause?

Answer 1

uncontrolled cell growth

Question 2

what are acquired mutations?

Answer 2

mutations acquired after fertilisation

Question 3

what is a tumour?

Answer 3

mass of abnormal cells

Question 4

what are cancers?

Answer 4

tumours that invade and destroy surrounding tissue

Question 5

what are examples of genes that control cell division?

Answer 5

tumour suppressor genes and proto-oncogenes

Question 6

what do tumour suppressor genes do?

Answer 6

slow cell division, and produce proteins that cause cell death if there is a DNA copying error

Question 7

when are tumour suppressor genes inactivated?

Answer 7

if there is a mutation in the DNA sequence

Question 8

what is self destruction of cells called?

Answer 8

apoptosis

Question 9

what happens in tumour suppressor genes if there is a mutation?

Answer 9

protein is not produced and the rate of cell division

Question 10

what do proto-oncogenes do?

Answer 10

controls cell division and initiates DNA replication

Question 11

what happens to a proto-oncogene if there is a mutation in the DNA sequence?

Answer 11

effect of the proto-oncogene is increased

Question 12

what is a mutated proto-oncogene called?

Answer 12

an oncogene

Question 13

what happens to a proto-oncogene when functioning is normal?

Answer 13

stimulate cell division by producing proteins that make cells divide

Question 14

what happens to proto-oncogenes when there is a mutation?

Answer 14

gene becomes overactive

rate of cell division increases so cells divide continuously

Question 15

what is a malignant tumour?

Answer 15

cancer
grows rapidly
invade and destroy surrounding tissues
cells can break off and spread via the bloodstream or lymph system

Question 16

what is a benign tumour?

Answer 16

not cancer
grow slower
covered in fibrous tissue
often harmless but can cause blockages and put pressure on organs

Question 17

what are the differences between tumour cells and normal cells?

Answer 17

tumour are.. 
irregular shape 
nucleus larger and darker 
may be more than one nucleus 
don't produce all the proteins needed to function correctly 
different antigens on surface 
don't respond to growth regulating processes
divide by mitosis more frequently

Question 18

what can abnormal methylation of cancer related genes lead to?

Answer 18

tumour growth

Question 19

what is methylation?

Answer 19

adding a methyl group onto something (-CH3)

Question 20

what does methylation of DNA regulate?

Answer 20

gene expression - whether or not a gene is transcribed and translated

Question 21

what does normal methylation play a role in?

Answer 21

normal body processes

Question 22

what types of methylation are an issue?

Answer 22

hypermethylation and hypomethylation

Question 23

what is hypermethylation?

Answer 23

more methyl groups attached

Question 24

what happens in hypermethalation of tumour suppressors?

Answer 24

genes are not transcribed
proteins they produce to slow cell division aren’t made
cells grow uncontrollably by mitosis=tumours

Question 25

what happens in hypomethylation of proto oncogenes?

Answer 25

act as oncogenes
increases the production of proteins which encourage cell division
stimulate cells to divide uncontrollably= tumour formation

Question 26

what can contribute to breast cancer?

Answer 26

increased oestrogen

Question 27

why can oestrogen contribute to breast cancer?

Answer 27

if this is a proto-oncogene= permanently turned on= cell division

stimulates breast cells to divide and replicate, more cell division increases the chance of mutations
if cells become cancer- replication replication further assisted by oestrogen which helps tumours to form quickly

can introduce mutations directly into DNA of breast cells