Evaluating Stem Cells
Laura Armstrong & Joe Wolfensohn
Teachers
Contents
Recall Questions
This topic requires prior knowledge of stem cells and mitosis to understand how stem cells can be applied in therapy.
What are meristems?
Stem cells from the growing regions of plants.
Which type of stem cell can turn into any type of cell?
Embryonic stem cells.
What is differentiation?
When a cell becomes specialised.
Topic Explainer Videos
Check out these @JoeDoesBiology videos that explain using stem cells in medical treatments and therapeutic cloning, then read the study notes. Once you’ve gone through them, don’t forget to try the practice questions!
Uses of Stem Cells & Evaluation
Uses of Stem Cells
|
Type of Stem Cell |
Example Use |
Source |
|
Embryonic |
Replace damaged spinal cord cells. |
Early embryos. |
|
Adult (bone marrow) |
Treat blood diseases like leukaemia. |
Bone marrow. |
|
Plant stem cells |
Clone plants quickly, preserve rare species. |
Meristem tissue in plants. |
Evaluating the Use of Stem Cells
Embryonic Stem Cells – Advantages:
- Can become any cell type, making them highly versatile.
- Rapid division: Easy to grow in the lab for large-scale treatments.
- Potential to treat many conditions: Including paralysis, diabetes, heart disease.
Embryonic Stem Cells – Disadvantages:
- Ethical issues: Obtained from destroyed embryos- some view this as destroying potential life.
- Risk of tumour formation: Due to uncontrolled division of stem cells.
- Immune rejection: Cells may not match the patient and may be rejected by their immune system.
Adult Stem Cells – Advantages:
- No ethical concerns: Taken from living donors (e.g. bone marrow) who can give consent.
- No rejection risk (if from the same patient): Safe for transplants.
- Already used successfully: E.g., in bone marrow transplants for blood cancers.
Adult Stem Cells – Disadvantages:
- Can only develop into a limited range of cells (e.g. blood cells only).
- Harder to grow and manipulate in the lab.
- May accumulate mutations as donor ages
Therapeutic Cloning
Definition:
Therapeutic cloning is a process where an embryo is created with the same DNA as the patient. This is done to grow stem cells that are genetically identical to the patient’s cells.
No answer provided.
How It Works:
1. A nucleus is taken from a patient’s body cell.
2. This nucleus is inserted into a donor egg cell that has had its nucleus removed.
3. The egg is stimulated to divide and form an embryo.
4. Stem cells are extracted from the embryo and grown in the lab.
5. These stem cells can develop into any cell type and can be used to replace damaged tissues in the patient.
Advantages of Therapeutic Cloning:
- No rejection – cells are genetically identical to the patient.
- Can treat diseases like Parkinson’s, diabetes, spinal injuries.
- Source of embryonic stem cells which can differentiate into any cell type.
Disadvantages & Ethical Concerns:
- Involves embryo destruction – raises ethical concerns.
- Some believe it’s unethical to create embryos just for research.
- Still experimental – success in treatments is limited so far.
- Risk of tumour development if cells grow uncontrollably.
Key Terms
- Therapeutic cloning – making a genetically identical embryo to supply matching stem cells.
- Rejection – when the immune system attacks foreign cells.
- Embryonic - obtained from an early stage embryo.
No answer provided.
Exam Tips
For evaluation questions, include benefits AND drawbacks, and explain both clearly.
If provided with information in an evaluate style question, you can use this in your answer but always add value to it. For example, if you are told in the question that stem cells divide rapidly, you can use this as a potential issue by adding… because stem cells divide rapidly, this could lead to tumour formation and potentially cancer in the patient.
No answer provided.
Evaluate the use of embryonic stem cells and adult stem cells from a donor in the treatment of a patient. (6 marks)
-
Embryonic stem cells:
-
Can become any type of cell, so useful for treating many conditions.
-
Can be grown easily in the lab in large numbers.
-
Raise ethical concerns as embryos are destroyed to obtain them.
-
Risk of immune rejection if not from the patient.
-
Possible risk of tumour formation due to rapid division.
-
Adult stem cells (from a donor):
- No ethical concerns – taken from living donors (e.g. bone marrow) who can give consent.
- Can only become a limited range of cells so are not able to treat as many different diseases.
- Risk of rejection if donor is not a match.
More Practice
Try to answer the practice question from the TikTok video on your own, then watch the video to see how well you did!