This topic summary covers Knowledge Organiser within Cloning for GCSE Biology. Cloning techniques, applications, and ethical considerations It is section 11 of 12 in this topic. Use this topic summary to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 11 of 12
Practice
25 questions
Recall
20 flashcards
Knowledge Organiser
Key Terms
- Clone — genetically identical organism
- Adult cell cloning — nucleus from body cell into enucleated egg
- Tissue culture — growing cells in sterile medium
- Surrogate mother — carries the cloned embryo
- Therapeutic cloning — cloning for stem cells, not reproduction
- Dolly the sheep — first mammal cloned from adult body cell (1996)
Dolly Steps (NINES)
- Nucleus taken from donor body cell
- Into enucleated egg cell (nucleus removed)
- Nucleus inserted into egg
- Electric shock triggers cell division
- Surrogate mother carries embryo to term
Natural Clones
- Identical twins — fertilised egg splits
- Plant runners — strawberries
- Bulbs — tulips, daffodils
- Tubers — potatoes
- Binary fission — bacteria
Advantages and Concerns
- Advantages: preserve endangered/rare species; rapidly produce large numbers of identical plants (tissue culture); produce animals with desirable traits at scale; therapeutic cloning could provide immune-compatible replacement tissue
- Concerns — process: very low success rate (Dolly required 277 attempts); cloned animals may show premature ageing or health problems (Dolly developed arthritis and lung disease, dying at 6 — half the normal lifespan)
- Concerns — reduced variation: a population of clones has identical alleles — one disease or change in environment could wipe out the entire population
- Therapeutic cloning: cloned embryo provides stem cells genetically identical to the patient, so replacement tissue would not be rejected by the immune system
- Reproductive cloning of humans: illegal in the UK and most countries; subject to ongoing ethical debate
Common Mistakes
- Forgetting to mention the enucleated egg cell: In adult cell cloning, the nucleus must be removed from the egg cell before the donor nucleus is inserted — omitting this step loses a mark.
- Saying the surrogate mother contributes genes: The clone is genetically identical to the nucleus donor, not the surrogate — the surrogate provides the environment, not the DNA.
- Claiming clones are phenotypically identical to the original: Clones have identical DNA but may differ in appearance and behaviour due to environmental influences on gene expression.
- One-sided ethics answers: Evaluate questions require arguments for AND against cloning — a fully one-sided answer cannot reach the top mark band.
- Confusing tissue culture with adult cell cloning: Tissue culture produces cloned plants from cells in sterile medium; adult cell cloning uses nuclear transfer to clone animals — they are distinct processes.
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Practice Questions for Cloning
What is the name of the first mammal to be cloned from an adult cell?
What is the process called when a plant is grown from a cutting?
Quick Recall Flashcards
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