Stem Cells Flashcards
Describe what totipotent cells are
Totipotent cells are cells that differentiate into itself and any type of body cell in an organism.
Only present in mammals after the first few cell divisions, after which the embryonic stem cells become pluripotent.
What is the difference between pluripotent, multipotent and unipotent stem cells.
Pluripotent stem cells can specialise into any type of body cell except extra embryonic tissues i.e placenta
Multipotent cells are able to differentiate into few types of body cells e.g bone marrow cells can form both white and red blood cells.
Unipotent cells are able to differentiate into one type of cell and itself
How does a totipotent cell become specialised?
Under different conditions different genes are expressed and switched off.
Genes that are expressed get transcribed into mRNA and the translated into proteins.
Proteins produced modify the cells i.e determine the cell structure and control cell processes including expression of more genes.
Changes to the cells as a result of these proteins results in the cell becoming specialised.
ONCE SPECIALISED STAYS SPECIALISED.
Name and describe and example of a cell type produced by unipotent stem cells
Cardiomyocytes can generate new cardiomyocytes through the cell cycles to build and replace heart muscle.
Describe the uses stem cells in treating human disorders
Pluripotent cells can divide in unlimited numbers
Bone marrow transplants can be used to replace faulty bone marrow that produce abnormal blood calls in patients
- successful treatment for leukaemia and lymphoma
Describe how induced pluripotent stem cells (iPS) are produced.
Process involves reprogramming specialised adult body cells so they become pluripotent.
Made to express a series of transcription factors that are normally associated with pluripotent cells causing the cells to express genes associated with pluripotency.
How are transcription factors introduced to form iPS cells
Transcription factors can be introduced by infecting the cell with a specifically modified virus
Virus has genes in its DNA which codes for the transcription factors so when infecting the cell, genes are passed into the adult cells DNA
Not currently utilised as more research is required to to investigate how similar iPS cells are to actual pluripotent embryonic stem cells.
