AQA GCSE Biology Foundation (8461), Foundation tier · Inheritance, variation and evolution › Variation and evolution
Practise Cloning. 6 exam-style questions plus unlimited generated ones on this subtopic, at up to four difficulty levels, with full mark schemes and a progress tracker. Free, no account needed.
Four ways to produce genetically identical organisms: cuttings, tissue culture, embryo transplants and adult cell cloning, plus their benefits, risks and ethical objections. This is in GCSE Biology only, not in Combined Science. Expect 'describe the steps' and 'evaluate' questions.
Key facts
Clone = genetically identical organism
Cuttings: older, simple method used by gardeners; many identical plants from one parent
Tissue culture: small groups of plant cells → identical plants; preserves rare species; used in nurseries
Embryo transplant: split the cells of an early embryo before they specialise → transplant into host mothers
Adult cell cloning: remove egg nucleus → insert adult body cell nucleus → electric shock → embryo → womb
An adult cell clone is genetically identical to the animal that gave the body cell nucleus
Main risk: no variation, so a disease could affect all the clones
Notes
Cloning plants
Cuttings: an older, simple method used by gardeners to produce many identical new plants from a parent plant. A piece of the plant, such as a shoot with leaves, is cut off and grown into a new plant.
Tissue culture: small groups of cells from part of a plant are used to grow identical new plants, on a sterile medium containing nutrients and plant hormones.
Tissue culture is important for preserving rare plant species, and is used commercially in plant nurseries.
Cloning animals
diagram
Embryo transplants: cells are split apart from a developing animal embryo before they become specialised, then the identical embryos are transplanted into host mothers. The offspring are identical to each other, but not to their parents.
Embryo transplants: one embryo split into several identical ones.
Adult cell cloning, step 1: the nucleus is removed from an unfertilised egg cell.
Step 2: the nucleus from an adult body cell, such as a skin cell, is inserted into the egg cell.
Step 3: an electric shock stimulates the egg cell to divide to form an embryo. The embryo cells contain the same genetic information as the adult skin cell.
Step 4: when the embryo has developed into a ball of cells, it is inserted into the womb of an adult female to continue its development.
Adult cell cloning: the clone is identical to the animal that gave the nucleus.
Benefits, risks and objections
Benefits: many identical plants or animals with useful characteristics can be produced quickly; rare species can be preserved; cloned animals might be used to produce substances for medicine.
Risks: clones have no genetic variation between them, so a new disease or a change in the environment could affect them all; some cloned animals have had health problems or shorter lives.
Objections: some people have ethical objections, such as concern for animal welfare or fears that it could lead to cloning humans.
Don’t lose marks
Saying the clone is identical to the egg donor or the host mother. It is identical to the nucleus donor.
Saying the egg is fertilised in adult cell cloning. It is an unfertilised egg cell, stimulated to divide by an electric shock.
Saying calves from embryo transplants are identical to their parents. They are identical to each other.
Forgetting that the embryo cells must be split before they become specialised.
More tips
Memory tricks
Adult cell cloning in four words: out, in, shock, womb.
A clone matches whoever gave the NUCLEUS.
Embryo transplant offspring are copies of each other, not of their parents, because the embryo came from sexual reproduction.
Exam technique
In 'describe' questions, give the steps in the right order.
Use precise terms: unfertilised egg cell, nucleus, body cell, electric shock, embryo, womb, host mother.
For 'evaluate' questions, include benefits, risks and an ethical point, then give a conclusion.
What each grade needs
What you need to be able to do, from the first marks up to the top grade.
Grade 3
Define a cloneAn organism that is genetically identical to another.
Grade 4
Describe taking cuttingsGardeners cut a piece from a parent plant and grow it into a new, identical plant.
Grade 5
Describe tissue culture and its usesSmall groups of cells from part of a plant are grown into identical plants, to preserve rare species or for nurseries.
Quick recall
Cover the answers and test yourself. The app has these as flashcards that come back just before you'd forget them.
In adult cell cloning, what is used to stimulate the egg cell to divide to form an embryo?
An electric shock
Explain why the nucleus was removed from the egg cell of sheep B.
So that the embryo only contains the genetic information from sheep A
In adult cell cloning, from which type of cell is the nucleus removed?
An (unfertilised) egg cell
The steps in adult cell cloning are given below, but they are in the wrong order. A The nucleus is removed from an unfertilised egg cell. B An electric shock stimulates the egg cell to divide and form an embryo. C A nucleus from a body (skin) cell of the animal to be cloned is inserted into the egg cell. D The embryo is inserted into the uterus of an adult female (a surrogate mother). Write the letters in the correct order.
A, C, B, D
Sample questions
Written for this site in the style of AQA exam questions. They are not taken from real past papers.
Question 1Easy4 marks
Plants and animals can be cloned in several ways.
(a) Which cloning method involves splitting apart the cells of a developing animal embryo before they become specialised? Tick (✓) one box.[1]
Adult cell cloning
Cuttings
Embryo transplants
Tissue culture
(b) Which method is an older, simple way that gardeners use to produce many identical new plants from a parent plant? Tick (✓) one box.[1]
Adult cell cloning
Cuttings
Embryo transplants
Selective breeding
(c) Tissue culture uses small groups of cells from part of a plant to grow identical new plants. Give one reason why tissue culture is important.[1]
(d) In adult cell cloning, what is used to stimulate the egg cell to divide to form an embryo?[1]
Show the answer and mark scheme
(a)Answer: Embryo transplants
(b)Answer: Cuttings
(c)Answer: Preserving rare plant species / producing large numbers of identical plants commercially in nurseries
preserving rare plant species / producing many identical plants for nurseries (commercially)
(d)Answer: An electric shock
an electric shock
Question 2Medium6 marks
Scientists used adult cell cloning to produce a lamb. • The nucleus was removed from an unfertilised egg cell taken from sheep B. • The nucleus from a skin cell of sheep A was inserted into this egg cell. • The embryo that developed was placed in the uterus of sheep C.
(a) Describe what was done to make the egg cell develop into an embryo after the nucleus from sheep A was inserted.[2]
(b) Which sheep is the lamb genetically identical to? Explain your answer.[2]
(c) Explain why the nucleus was removed from the egg cell of sheep B.[1]
(d) Give one possible benefit of adult cell cloning in agriculture.[1]
Show the answer and mark scheme
(a)Answer: An electric shock stimulated the egg cell to divide (by mitosis) to form an embryo, a ball of cells
an electric shock (was given)
to stimulate the egg cell to divide / to form an embryo (a ball of cells)
(b)Answer: Sheep A, because the nucleus containing the genetic information came from sheep A
sheep A
the nucleus / genetic information / DNA came from sheep A
(c)Answer: So that the embryo only contains the genetic information from sheep A
so the embryo contains only the genetic information of sheep A / so there are not too many chromosomes
(d)Answer: Many copies of an animal with a desirable characteristic, e.g. high milk yield, can be produced
produce many animals with a desirable characteristic (e.g. high milk yield) / copy the best animals