Stem cells: compare potential, matching and ethical choices
| English | Français |
|---|---|
| stem cell/stem sel/ | stem cell |
| meristem/ˈmerɪstəm/ | meristem |
| therapeutic cloning/ˌθerəˈpjuːtɪk ˈkləʊnɪŋ/ | therapeutic cloning |
What would explain this observation?
- A cell that can divide and specialize may help replace damaged tissue. The possible benefit depends on which cell types it can produce and on evidence about risks.
- Start with a prediction. State the quantities or features you would compare, then decide what evidence could distinguish two explanations.
Build the model
- A stem cell 干细胞 is undifferentiated and can produce more stem cells and some differentiated cells. Human embryonic stem cells can differentiate into most human cell types. Adult bone-marrow stem cells can form several cell types, including blood cells. Plant meristems 分生组织 can form any plant cell type throughout life.
- stem cell: An undifferentiated cell able to divide and give rise to some specialized cells; meristem: Plant tissue containing cells that can continue dividing and differentiating; therapeutic cloning 治疗性克隆: Production of an embryo genetically matching a patient for potential stem-cell treatment.
Which comparison matches the stated GCSE model?
Therapeutic cloning produces an embryo with the patient’s genes, so its stem cells offer a genetic match and reduced rejection in the specification’s model. Potential applications include conditions such as diabetes or paralysis. These are potential benefits, not guaranteed cures. Viral transfer and ethical or religious objections must be considered with the evidence.
Match each technical term to its precise meaning.
Use the definitions to distinguish related quantities and processes.
Choose evidence that can test it
- Therapeutic cloning produces an embryo with the patient’s genes, so its stem cells offer a genetic match and reduced rejection in the specification’s model. Potential applications include conditions such as diabetes or paralysis. These are potential benefits, not guaranteed cures. Viral transfer and ethical or religious objections must be considered with the evidence.
- Evaluate a supplied fictional research proposal using benefit, evidence, risk and value judgement as separate headings. AQA does not require laboratory stem-cell techniques. For plants, compare rapid economical production of genetically identical disease-resistant crops with conserving rare plants and retaining genetic diversity.
Which two habits make the investigation or model in this case more defensible?
Evaluate a supplied fictional research proposal using benefit, evidence, risk and value judgement as separate headings. AQA does not require laboratory stem-cell techniques. For plants, compare rapid economical production of genetically identical disease-resistant crops with conserving rare plants and retaining genetic diversity.
Work from known quantities
- State the known values and their units. Choose the relation because its assumptions fit this case, then rearrange before substitution.
- Known: an approved model nursery starts with five identical plant clones and each produces four new clones. New clones = 5×4=20. If the originals remain, total plants =25. The number increases, but cloning alone does not add genetic variety; a shared susceptibility could affect the whole group.
Six retained model parent plants each produce three new clones. Find the total including parents. Use the same sequence: known quantities → model → relation → substitution → unit and interpretation.
Six retained model parent plants each produce three new clones. Find the total including parents.
The result is 24 plants. Known: an approved model nursery starts with five identical plant clones and each produces four new clones. New clones = 5×4=20. If the originals remain, total plants =25. The number increases, but cloning alone does not add genetic variety; a shared susceptibility could affect the whole group.
Check the conclusion and its limits
- Adult bone-marrow stem cells are not assumed to form every body cell type. Genetic matching does not remove every medical risk. Cloning a rare species can increase its number, while habitat protection and genetic diversity still require attention.
- Return to the original observation. Explain what the result supports, which conditions it assumes, and one way to test a competing explanation.
A genetically matched stem-cell treatment is guaranteed to have no risks. This claim is false: Adult bone-marrow stem cells are not assumed to form every body cell type. Genetic matching does not remove every medical risk. Cloning a rare species can increase its number, while habitat protection and genetic diversity still require attention.
Stem cells: compare potential, matching and ethical choices: Therapeutic cloning produces an embryo with the patient’s genes, so its stem cells offer a genetic match and reduced rejection in the specification’s model. Potential applications include conditions such as diabetes or paralysis. These are potential benefits, not guaranteed cures. Viral transfer and ethical or religious objections must be considered with the evidence.
A genetically matched stem-cell treatment is guaranteed to have no risks.
Adult bone-marrow stem cells are not assumed to form every body cell type. Genetic matching does not remove every medical risk. Cloning a rare species can increase its number, while habitat protection and genetic diversity still require attention.
An undifferentiated cell able to divide and give rise to some specialized cells: write the technical term.
stem cell means An undifferentiated cell able to divide and give rise to some specialized cells.