3. Cancer

Question 1

What are acquired mutations

Answer 1

Mutations that occur in individual cells after fertilisation ( in adulthood)

If these occcur in genes that control rate of cell Divsion ( by Mitosis) it can cause uncontrolled cell divsion

Causing tumour - mass of abnormal cells

Question 2

what are cancers

Answer 2

Rumour that invaded and destroyed surrounding tissues

Question 3

What 2 types of gene that could control cell divson called ?

Answer 3

Tumour suppressor genes

Proto - oncogenes

Mutations in these genes can cause cancer

Question 4

Tumour suppressor genes

Answer 4

When functioning normally tumour suppressor genes slow down cell divsion by producing proteins that stop cells dividing or cause them to self destruct (apoptosis)

If mutation occurs here then the gene will be inactivated.
Protein it codes for isn’t produced and the cells divide uncontrollably resulting in tumour

Question 5

What is apoptosis ?

Answer 5

Programmed death

Damaged cells / or infected reach end of functional life - destroyed

Question 6

Proto oncogenes

Answer 6

when functioning normally proto- oncogenes stimulate cell divsion by producing proteins that Make cells divide.

If mutation occurs here the genes can become overreactive and it stimulates the cells to divide uncontrollably so rate of division increases - tumour

Question 7

What is mutated proto- oncogene called?

Answer 7

Oncogene

Question 8

Name 2 different cancerous rumours

Answer 8

Malignant tumours

Benign tymours

Question 9

Malignant tumour

Answer 9

Cancers.

Grow rapidly and invade / destroy surrounding tissues.

They can break off the tumour and spread to other parts of the body in the bloodstream and lymph system

Question 10

Benign tumours

Answer 10

Not cancerous

Grow slower than making emend tumours

Covered in friborous tissue that stops cells invading other tissues

Harmless but can cause blockades and put pressure on organs

Can become malignant

Question 11

How do tumour cells differ from normal cells?

Answer 11

Nucleus larger and darker

Irregular shape

Don’t produce all proteins needed

Different antigen

Divide by mitosis more frequently

Question 12

What 3 factors are thought to lead to growth of tumours ?

Answer 12

Abnormal methylation of dna and increased exposure to oestrogen

Question 13

What does methylation mean?

Answer 13

Adding methyl group onto something

Question 14

Why is methylation needed ?

Answer 14

Regulates gene expression - controls whether or not gene is transcribed and translated

Key in body

Question 15

When does methylation become a problem ?

Answer 15

Too much - hypermethylation

Too little - hypomethylation

Tumours can grown from abnormal methalatuon of cancer related genes

Question 16

What happens when tumour suppressor genes are hypermethylated ?

Answer 16

Genes aren’t transcribed

So protein they produce to slow down cell division aren’t made.

Cells divide uncontrollably by mitosis and tumours can develop.

Question 17

What happens when hypomethylation or proto oncogenes occurs ?

Answer 17

Causes them to act as oncogenes

More production of protein that encourageAge cell division

Stimulates cells to divide uncontrollably- formation of tumours

Question 18

Increased exposure to oestrogen may be the result of what ?

Answer 18

Starting menstratuon earlier than usual

Starting menopause later than usual

Or oestrogen containing drugs

Question 19

Name 3 ways oestrogen can contribute to development of some Breast cancers ?

Answer 19

• stimulate certain breast cells to divide and replicate. More divisions taking place means higher chance of mutations occurring and so increases change of cancerous cells
• stimulates divsion meaning if cells do become cancerous their rapid replication could be further assisted by oestrogen - tumour quicker
• can introduce mutations directly into dna of breast cells - increases chance of cancerous cells

Question 20

What does HRT stand for ?

Answer 20

Hormone replacement therapy

Increase oestrogen levels in some wowmene in order to treatment symptoms caused during menopause