Gene mutation & cancer Flashcards
Addition
-Base is added into the base sequence
-Results in a frameshift
-So the whole sequence of bases after the mutation is altered
Deletion
-Base is removed from the base sequence
-Results in a frameshift
-So the whole sequence after the mutation is altered
Substitution
-Base or baes are substituted
-Maybe a silent mutation
-Or a missense mutation, resulting in a different amino acid being coded for
Inversion
-Segment of DNA flips around
-Resulting in one or more amino acids being changed in the sequenced
Duplication
-One or more bases are repeated
-Resulting in a frameshift after the mutation
Translocation
-Bases are separated from one chromosome and become inserted into another chromosome
-Have a significant effect on gene expression
-Leading to reduced fertility and the development of cancers
Causes of mutations
-X rays
-UV light
-Tobacco smoke
For cancer to occur
-Tumour suppressor genes turn off
-Oncogenes are turned on
Proto-oncogenes
Growth factors attach to a receptor protein on the cell surface membrane and via relay proteins in the cytoplasm, switch on the gene needed for DNA replication.
Oncogenes
A mutation can cause proto-oncogenes to mutate into oncogenes
Affects cell division in 2 main ways
-Receptor protein on cell surface membrane is permanently activated
-my code for a growth factor that is then produced in excessive amounts, stimulating exercise cell division
How oestrogen can promote cancer
-Oestrogens are produced by fat cells in breast tissue post-menopause
-These stimulate breast cancer
-Tumour cells develop, and oestrogen concentrations increase further, also WBC are drawn to the tumour
-Leading to increased development of the tumour
How oestogen stimultaes cancer
-Oestrogen binds to a gene which promotes transcription
-Cause proto-oncogenes of cells in breast tissue to develop into oncogenes
-Cell division is stimulated when the oestrogen-receptor-coregulator complex binds to the DNA.
