2. cancer

Question 1

muations that occur after fertilisation

Answer 1

acquired mutations

Question 2

tumour supressor genes

Answer 2

1. inactivated if mutation occurs
2. when functioning slow cell division by producing proteins that stop cells dividing or causes them to self destruct (apoptosis)
3. mutation = protein not produced. cells divide uncontrollably = tumour

Question 3

proto-oncogenes

Answer 3

1. effect of proto-oncogene increased by mutation -> oncogene
2. when functioning normally stimulate cell division by producing proteins that make cells divide
3. mutation = overactive. cells divide uncontrollably = tumour

Question 4

benign tumour

Answer 4

not cancerous
grow slower
covered in fibrous tissue (stops cells invating other tissue)
harmless but can cause blockages and put pressure on organs
some can become malignant

Question 5

malignant tumour

Answer 5

cancer
grow rapidly
invade / destroy surrounding tissue
cells can break off tumours and spread to other parts of body via blood stream or lymphatic system

Question 6

differency between cancer cells and normal cells

Answer 6

irregular shape 
nucleus larger and darker 
different antigens 
dont respond to growth regulating processes 
divide more frequently

Question 7

methylation and tumour suppressor genes

Answer 7

hypermethylation
genes not transcribed
proteins they produce to slow cell division not made
divide uncontrollably

Question 8

methylation and proto-onco genes

Answer 8

hypomethylation
act as oncogenes
increases production of proteins that encourage cell division
divide uncontrollably

Question 9

oestrogen

Answer 9

increased exposure thought to increase womans risk of developing breast cancer

Question 10

theorys behind oestrogen and breast cancer

Answer 10

1. can stimulate breast cells to divide and replicate. more cell division = increased chance of mutations occurring = increase chance of being cancerous
2. if cells do become cancerous rapid replication could be further assisted by oestrogen
3. suggested oestrogen is able to introdcue mutations directly into DNA of breast cells = increases chance of becoming cancerous

Question 11

risk factors

Answer 11

1. genetic factors - specific inhereited alleles = more likely to get cancer
2. environmental factors - exposure to radiation, life style choices such as smoking, increased alcohol consumption and high fat diet linked to increased chance of developing cancer