Stem Cells Flashcards
Cells become specialised through the process of cellular ______________.
differentiation
Functions of stem cells
Differentiation;
Mitosis;
4 types of stem cells
Totipotent
Pluripotent
Multipotent
Unipotent
________________ cells occur only for a limited time in early mammalian embryos.
Totipotent
Totipotent stem cells can divide by [1] and produce [2] type of body cell.
[1] mitosis
[2] ANY
TRUE or FALSE:
During development, totipotent cells translate only part of their DNA, resulting in cell specialisation.
TRUE
Pluripotent stem cells are found in ___________
embryos
Functions of pluripotent stem cells
- Divide in unlimited numbers;
- Produce MOST cell types
- Used to treat human disorders
Stem cells found
in mature mammals
multipotent
unipotent
Multipotent stem cells produce ________ cell types
SOME
Unipotent stem cells in the heart can differentiate into ___________
cardiomyocytes
Myelodysplastic syndromes (MDS) are a group of malignant cancers. In MDS, the bone marrow does not produce healthy blood cells.
Haematopoietic stem cell transplantation (HSCT) is one treatment for MDS. In HSCT, the patient receives stem cells from the bone marrow of a person who does not have MDS. Before the treatment starts, the patient’s faulty bone marrow is destroyed.
For some patients, HSCT is an effective treatment for MDS. Explain how (3 marks).
- Stem cells differentiate/produce healthy (blood) cells;
- No MDS/faulty/cancerous (blood) cells;
- Stem cells divide/replicate by mitosis;
Scientists have investigated the use of different types of stem cell to treat damage to the heart after a myocardial infarction. During a myocardial infarction, a number of different cell types in the heart die. This includes cardiomyocytes which are heart-muscle cells.
Embryonic pluripotent stem cells (ESCs) can divide and differentiate into a wide range of different cell types.
Using the information given, suggest one reason why ESCs might be suitable to treat damage to the heart.
(ESCs produce MOST types of cell)
So they can replace any type of heart cell;
Embryonic pluripotent stem cells (ESCs) have not yet been used to treat people who have had a myocardial infarction. This is because of concern that the use of ESCs might lead to more harm to the person.
Suggest how putting ESCs into a person’s heart might lead to more harm to the person (3 marks).
- Differentiating into the wrong types of cells.
- Might divide out of control;
- Leading to tumour / cancer;
Haematopoietic stem cell transplantation (HSCT) is a long-term treatment for sickle cell disease (SCD). In HSCT, the patient receives stem cells from the bone marrow of a person who does not have SCD.
The donor is often the patient’s brother or sister. Explain why.
Less chance of rejection
by immune system
(from brother/sister);
What are iPS cells?
induced pluripotent stem cells
Induced pluripotent stem (iPS) cells can be produced from adult [1] cells using appropriate ‘reprogramming’ protein [2] factors.
[1] somatic
(e.g. keratinocytes in the skin)
[2] transcription
Suggest how transcription factors can reprogramme cells to form iPS cells (2 marks).
- Bind to DNA promoter region;
- Stimulate / inhibit RNA polymerase
- Increase / decrease transcription
Advantages of using iPS cells
- Somatic cells easy to obtain;
- Divide in unlimited numbers;
- Produce MOST cell types;
- Used to treat human disorders;
- Less chance of rejection by immune system
(as using somatic cells that originated from patient);
Disadvantages of using iPS cells
- Takes a long time to differentiate into desired specialised cell;
- Cells generated ‘in vitro’ (i.e. in cell culture) may not function when transplated back into humans;
