2.2.4Structure and Functions in Living Organisms: Part 1
Stem Cells in Medicine: Advantages and Disadvantages
5 min read 5 parts Lesson 6 of 36 Unit quiz
Section 1 of 5Sources of Stem Cells
Embryonic stem cells
- These come from early embryos and can differentiate into almost any type of cell in the body.
Adult stem cells
- These are found in tissues such as bone marrow and can form only a limited range of cell types.
Plant meristems
- Plants have stem cells in meristem tissue at the tips of roots and shoots, which can become any plant cell type.
Differentiation
- Under the right conditions in the laboratory, stem cells can be made to specialise into the cells needed for treatment.
Section 2 of 5Medical Uses
Medical Uses
Bone marrow transplants
- Transplanted stem cells replace blood cells in patients with diseases such as leukaemia.
Replacing damaged tissue
- Stem cells could be used to grow new tissue to repair damage, such as in burns or heart disease.
Nervous system injury
- Research aims to use stem cells to replace nerve cells damaged by spinal injury, though this is still being developed.
Diabetes research
- Scientists are investigating whether stem cells can replace the insulin-producing cells lost in type 1 diabetes.
Section 3 of 5Advantages and Disadvantages
Advantage: new treatments
- Stem cells may treat conditions that are currently incurable, by replacing cells that have been lost or damaged.
Advantage: no waiting list
- Cells grown in the laboratory could reduce the need for donor organs, which are always in short supply.
Advantage: matching
- Cells can be grown from the patient's own tissue, which should reduce the risk of the body rejecting them.
Disadvantage: ethical objections
- Obtaining embryonic stem cells involves destroying an embryo, and some people believe this is wrong.
Disadvantage: risks
- Stem cells can divide uncontrollably and form tumours, and donated cells may carry viruses or be rejected.
Disadvantage: cost and difficulty
- Producing and controlling the growth of stem cells is technically difficult and expensive.
| Advantages | Disadvantages |
|---|---|
| Could cure currently untreatable diseases | Embryo destruction raises ethical concerns |
| Reduces dependence on organ donors | Risk of tumours or infection |
| Own cells reduce rejection | Expensive and technically difficult |
Section 4 of 5Evaluating the Issues
1
State the possible benefit to patients, such as the repair of a damaged organ.
2
State the risk, such as tumour formation, or the ethical concern about using embryos.
3
Decide which source of stem cells is involved, because adult stem cells raise fewer ethical objections than embryonic ones.
4
Weigh up the benefits against the risks and concerns for the particular treatment being proposed.
5
Reach a clear conclusion supported by at least one reason from each side.
Section 5 of 5Exam Checklist & Tips
2.2.4 – Key Points for the Exam
- Stem cell An unspecialised cell that can divide and differentiate into specialised cell types.
- Embryonic stem cell A stem cell taken from an early embryo that can become almost any cell type.
- Adult stem cell A stem cell found in adult tissue, such as bone marrow, with a more limited range of cell types.
- Rejection The immune response in which the body attacks transplanted cells that it recognises as foreign.
- Meristem Plant tissue containing stem cells that can differentiate into any plant cell type.
Common Mistakes
- Stating that stem cells are already used to cure every disease; many uses are still at research stage.
- Giving only ethical points when the question asks for advantages and disadvantages of both kinds.
- Saying adult stem cells can become any cell type;
- their range is more limited than that of embryonic stem cells.
- Writing that a treatment is 'bad' or 'good' without giving a reason.
Cambridge 9700 AS Biology
Core Formula
Magnification Triangle & Unit Conversion
Formula: M = I / A ⇔ A = I / M ⇔ I = M × A
Units: 1 mm = 1,000 μm = 1,000,000 nm.
Rule: Convert Image size (ruler mm) to μm by ×1,000 before dividing by Actual size.