Mutations And Genes (Miss Reynolds) Flashcards
Mutation
A change to the nucleotide sequence of DNA.
Mutagenic agent
Increase rate of mutations (above normal)
When do most mutations occur and why?
Interphase, longest stage
Substitution
One base is swapped for another
Addition
An extra base is added
Deletion
A base is removed
Which types of mutation cause a frame shift?
Addition and Deletion
Inversion
A sequence of bases is repeated.
Duplication
One or more bases repeated.
Tumour suppressor genes
Slow cell division.
Proto-oncogenes
Stimulate cell division.
When are proto-oncogenes switched on?
When growth factors bind to protein receptors on the cell surface membrane.
Oncogenes
Permanently switched on, even in the absence of growth factors, caused by a mutation.
Benign tumour
Not cancerous, slower growth, donโt invade other tissues and are most of the time harmless.
Malignant tumours
Uncontrolled growth / rapid, cancerous, can spread to other tissues
What does oestrogen cause in terms of cell division?
Increased cell division