Unit 1 : Stem Cells Flashcards
An embryo contains only a few unspecialised cells. What are these called?
Stem cells
What are stem cells?
Simple undifferentiated cells
What can stem cells do?
- continue dividing by cell division to produce more stem cells
- differentiate into a wide varity of specialised cell types
What are ‘embryonic stem cells’?
undifferentiated cells found in very early animal embryos and can form any cell type.
Where can embryonic stem cells be sourced from?
early embryos, umbilical cord and placenta.
What is an advantage of embryonic stem cells?
They grow rapidly and ae easy to culture.
What are adult stem cells?
Unspecialised cells found in certain organs in adults - bone marrow, blood, heart tissue.
What is a disadvantage of adult stem cells?
They are more difficult to grow and culture.
Where are ‘plant stem celss’ found?
In the APICAL growing points or MERISTEMS at the end of the shoots and the roots.
What is meant by ‘redifferentiate’?
Under certain conditions the specialisation of plant stem cells can be reversed. This allows scientists to produce large numbers of genetically identical plants in a very short time.
Which blood cancer can stem cells be used to treat?
Leukaemia
Ste cells can be used to produce new nervous tissue. What can this treat?
To treat Parkinson’s disease or paralysis due to spinal injuries.
How can stem cells help repair danaged joints?
To build new bone, tissue or cartilage.
How can they fight disease?
Stem cells can produce new immune cells which can fight disease.
How can stem cells be used in organ transplants?
To produce replacememt organs that match the patient’s tissue type, to stop organ rejection.
Fill in the gaps in the flow chart to explain how stem cells are used to treat leukaemia:
______ and _______ destroy cancerous blood cells in the patient.
Chemotherapy and radiotherapy
The patient’s _______ ________
stops producing new blood cells.
Bone marrow
Patient is given a transplant of bone marrow containing _______ _________ from a healthy matching donor.
Stem cells
Donor stem celss multiply and produce healthy _______ _______ in the patient.
Blood cellls
Chemotherapy and radiotherapy destroy patients white blood cells before the stem cell transplant. Hoe does this make the patient very vunerable?
It leaves the patient with no immune system.
Stem stills are at risk of dividing in an uncontrolled way. What can this cause?
it may cause tumours or unwanted cell types.
What ethical issues surround the use of stem cells?
- use of embryo in this way may be considered murder by some
- human rights of embryo are ignored
- religous grounds, feel that scientists are ‘playing God’
- may lead to cloning and designer babies
