topic 8 cancer Flashcards
what can mutations in genes cause?
uncontrolled cell growth
what are acquired mutations?
mutations acquired after fertilisation
what is a tumour?
mass of abnormal cells
what are cancers?
tumours that invade and destroy surrounding tissue
what are examples of genes that control cell division?
tumour suppressor genes and proto-oncogenes
what do tumour suppressor genes do?
slow cell division, and produce proteins that cause cell death if there is a DNA copying error
when are tumour suppressor genes inactivated?
if there is a mutation in the DNA sequence
what is self destruction of cells called?
apoptosis
what happens in tumour suppressor genes if there is a mutation?
protein is not produced and the rate of cell division
what do proto-oncogenes do?
controls cell division and initiates DNA replication
what happens to a proto-oncogene if there is a mutation in the DNA sequence?
effect of the proto-oncogene is increased
what is a mutated proto-oncogene called?
an oncogene
what happens to a proto-oncogene when functioning is normal?
stimulate cell division by producing proteins that make cells divide
what happens to proto-oncogenes when there is a mutation?
gene becomes overactive
rate of cell division increases so cells divide continuously
what is a malignant tumour?
cancer
grows rapidly
invade and destroy surrounding tissues
cells can break off and spread via the bloodstream or lymph system
what is a benign tumour?
not cancer
grow slower
covered in fibrous tissue
often harmless but can cause blockages and put pressure on organs
what are the differences between tumour cells and normal cells?
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
what can abnormal methylation of cancer related genes lead to?
tumour growth
what is methylation?
adding a methyl group onto something (-CH3)
what does methylation of DNA regulate?
gene expression - whether or not a gene is transcribed and translated
what does normal methylation play a role in?
normal body processes
what types of methylation are an issue?
hypermethylation and hypomethylation
what is hypermethylation?
more methyl groups attached
what happens in hypermethalation of tumour suppressors?
genes are not transcribed
proteins they produce to slow cell division aren’t made
cells grow uncontrollably by mitosis=tumours
what happens in hypomethylation of proto oncogenes?
act as oncogenes
increases the production of proteins which encourage cell division
stimulate cells to divide uncontrollably= tumour formation
what can contribute to breast cancer?
increased oestrogen
why can oestrogen contribute to breast cancer?
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
