3.8.2.3 gene expression and cancer and 3.8.3 genome project Flashcards
(17 cards)
how do cancers and tumours form
mutations in DNA/genes controlling mitosis can lead to uncontrolled cell division, forming a mass of abnormal cells
malignant tumours - cancerous and spread by metastasis
benign tumours - non cancerous
compare the main characteristics of benign and malignant tumours
benign:
grow slow, cells are specialised, have well defined boarders and do not spread by metastasis
malignant:
grow fast, cells are poorly specialised, poorly defined boarders and spread by metastasis
describe the function of tumour suppressor genes
they code proteins that inhibit the cell cycle or cause apoptosis of potential tumour cells.
how are tumour suppressor genes involved in the development of tumours
mutation in the base sequence ->produce a non-functional protein
describe the function of proto-oncogenes
code for proteins that stimulate cell division
how are oncogenes involved in the development of tumours
mutation in the DNA base sequence -> over production of proteins
what is an oncogene
a mutated form of a proto-oncogene
why do both alleles of a tumour suppressor gene need to be mutated compared to one mutation of an oncogene allel
1 functional allele of the tumour suppressor gene can still produce enough protein to slow the cell cycle or trigger apoptosis
but 1 mutated oncogene will produce enough proteins which lead to uncontrolled cell division
explain the link between epigenetics and cancer treatment
increasing DNA methylation/ decreasing histone acetylation will inhibit expression of cancer
decreasing DNA methylation/ increasing histone acetylation will stimulate expression of cancer
how does increased oestrogen concentration lead to the development of oestrogen positive breast cancer
increase of oestrogen will cause more oestrogen to bind to oestrogen receptors forming more oestrogen receptor complexes which act as transcription factors. increasing the number of transcription factors will increase binding to promoter region of genes that code for proteins which stimulate cell division.
why do drugs with a similar shape to oestrogen work as treatment to cancer
the drug will bind to the oestrogen receptor, preventing oestrogen from binding.
fewer transcription factors bind to promoter regions of genes that stimulate the cell cycle.
what is the genome
the complete set of genes in a cell
what is the proteome
the full set of proteins that a cell can produce
what is genome sequencing and why is it important
identifying DNA base sequences of an organism genome
this allows the amino acid sequence of proteins to be determined
how does genome sequencing allow for development of vaccines
identification of the pathogens proteome, therefore identifying potential antigens to use in the vaccine
what are applications of the genome sequencing project
identification of genes associated with genetic diseases, allowing for new targeted drugs to be developed and allow early prevention.
why cant the genome be translated into the proteome in complex organisms
presence of introns
