Normal differentiation and abnormal division Flashcards
What are differentiated cells?
Cells that are specialised for specific functions
What are tissues?
A group of differentiated cells which have the same function
What are organs?
Groups of tissues
What are totipotent cells?
Cells which can differentiate into any other cell type.
Where can you find totipotent cells.
Meristematic cells in plants
What are the regions of cells that are specialised and can produce a restricted range of cell types.
Adult stem cells.
What is a pluripotent cell?
A cell which is capable of giving rise to several different cell types
What is special about embryonic stem cells?
They have the ability to differentiate into any cell type.
Why does the repressor molecule attach to the operator?
So the transcription enzyme can not read the structural gene
Which gene produces the repressor molecule?
The regulator gene?
What happens to the repressor molecule when lactose is present?
Repressor molecule attaches to the inducer
What is the result of an open operator
The transcription enzyme can read the structural gene and produce b-galactosidase
What type of proteins do proliferation genes produce?
Proteins which promote cell divisions when an external sign is received. Such as an open wound.
What are un-mutated proliferation genes known as?
Proto-oncogenes.
What do oncogenes give?
Proteins with abnormal shapes which stimulate excessive cell division even in the absence of an external signal.
Why can oncogenes be thought of as dominant alleles?
A mutation only has to occur in one gene of the pair.
What do anti-proliferation genes produce?
Proteins which restrict cell division by operating at the cell cycle checkpoints
Why do both copies of the anti-proliferation gene need to mutate before control of the cell cycle is lost and a tumour starts to form.
One functioning gene can still produce the protein to inhibit the cell cycle
