5.4.2Use of Biological Resources
The Production of Cloned Mammals — Edexcel International GCSE Biology 4BI1 Revision Notes & Topical Questions
5 min read 4 parts Lesson 7 of 7 Unit quiz
Curriculum Equation Key قوانين الرقم الهيدروجيني والاتزان الأيوني - pH & Acid-Base Equilibrium FormulasFast Exam Solution
pH = -log[H⁺] | pOH = -log[OH⁻] | pH + pOH = 14 | [H⁺][OH⁻] = 10⁻¹⁴
Word Equation & Conditions: الرقم الهيدروجيني = -لوغاريتم تركيز أيون الهيدروجين | pH + pOH = 14
Location & Specifications: الاتزان الأيوني، كيمياء 3 ثانوي، التحصيلي، و AP Chemistry.
Section 1 of 4Adult Cell Cloning
This technique produced Dolly the sheep in 1996, the first mammal cloned from an adult cell.
1
The nucleus is removed from an unfertilised egg cell, leaving an enucleated egg.
2
A diploid nucleus is taken from a body cell of the adult to be cloned, for example a skin cell.
3
The adult nucleus is inserted into the empty egg cell.
4
A small electric shock stimulates the cell to divide by mitosis and form an embryo.
5
When the embryo is a ball of cells, it is implanted into the uterus of a surrogate mother.
6
The offspring that is born is genetically identical to the adult that donated the nucleus.
Section 2 of 4Benefits and Risks
Judge each point and say who is affected.
Benefit: conservation
- Benefit: conservation Cloning can help preserve endangered species by increasing their numbers.
Benefit: farming
- Benefit: farming Cloning lets farmers produce many animals with high yield, such as high milk production.
Risk: diversity
- Risk: diversity Clones are genetically identical, so a disease or change in conditions could harm all of them.
Risk: health
- Risk: health There is evidence that cloned animals may be less healthy, and many attempts fail.
Ethical concern
- Ethical concern Many people object to cloning, especially of humans, on moral grounds.
Section 3 of 4Transgenic Animals
Transgenic Animals
Transgenic
- Transgenic An animal that has had a gene from another species inserted into its genome.
Useful proteins
- Useful proteins The inserted gene can code for a human protein that the animal then makes, for example in its milk, for use as a medicine.
Cloning
- Cloning Once one useful transgenic animal exists, cloning can produce more animals with the same gene.
Link to genetic engineering
- Link to genetic engineering The process uses the same ideas as genetic modification of bacteria, but in animal cells.
Section 4 of 4Exam Checklist & Tips
5.4.2 – Key Points for the Exam
- Clone An organism that is genetically identical to another.
- Enucleated Having had the nucleus removed.
- Surrogate mother A female that carries an embryo that is not her own to birth.
- Transgenic Containing a gene from a different species.
- Diploid Having two sets of chromosomes in the nucleus.
Common Mistakes
- Saying the egg's own nucleus is kept; it is removed and replaced by a nucleus from the adult cell.
- Thinking the clone is a copy of the surrogate mother; it copies the nucleus donor.
- Writing that cloning increases genetic variation; clones share the same genes, so variation is reduced.
- Assuming that cloned animals are always healthy and identical in every way.
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