Cloning

What is meant by the term 'cloning' in biology?

Cloning is the process of producing genetically identical individuals.
Clones have exactly the same DNA as the original organism.

What are the 3 main types of cloning covered in GCSE Biology?

• Tissue culture (plant cloning)

• Cuttings (plant cloning)

• Embryo transplants and adult cell cloning (animal cloning)

What is tissue culture in plants, and how is it used?

• Tissue culture involves taking small groups of cells from a plant (often from the roots or shoots).

• These are grown in a sterile nutrient-rich medium with growth hormones.

• The cells grow into identical clones of the original plant.
  ✅ Used to quickly produce many plants from one parent, especially rare or endangered species.

What are the benefits of tissue culture in plants?

• Large numbers of plants produced quickly.

• Can be grown all year round in controlled conditions.

• Allows preservation of rare plants.

• Genetically identical – desirable traits like disease resistance are guaranteed.

How is cloning by cuttings carried out in plants?

• more widely used by gardners one

• A section of a plant (e.g. a stem or leaf) is cut off and planted in soil.

• With rooting hormone and care, the cutting grows into a new, identical plant.
  ✅ Simple, cheap, and can be done by gardeners or farmers.

How are animals cloned using embryo transplants?

• Egg cells from the best cow are artificially fertilised using sperm cells taken from the best bull

• This forms an embryo

• The developing animal embryo is then split apart many times before the cells of the embryo become specialised

• This forms many separate embryos that are genetically identical

• These cloned embryos are then transplanted into host mothers

• The calves born from these host mothers are all genetically identical to each other but not to the host mother

Why are embryo transplants useful in farming?

• Helps produce many genetically identical animals with desirable traits like fast growth or high milk yield.

• Faster than selective breeding alone.

How is adult cell cloning carried out?

• A body cell (e.g. skin cell) is taken from the animal to be cloned.

• The nucleus (which contains the DNA) is removed.

• An egg cell is taken from a female animal, and its nucleus is removed.

• The nucleus from the body cell is inserted into the empty egg cell.

• The egg cell is stimulated with an electric shock to start dividing by mitosis to form an embryo

• The embryo is implanted into the uterus of a surrogate mother.
  ✅ The new animal is a clone of the donor of the body cell.

What famous animal was created using adult cell cloning?

✅ Dolly the sheep was the first mammal cloned from an adult cell in 1996.
She was genetically identical to the sheep that donated the body cell.

What are the potential benefits of cloning?

• Preserving endangered species.

• Farming – produce animals with desirable characteristics so farmers can conistently ensure high quality livestock

• Medical research – study effects of genes and develop treatments.

• Cloning pets or prized animals.

• Tissue culture can help grow plants with specific features.

What are the concerns or problems with cloning?

• Reduced gene pool – less variation, makes species vulnerable to diseases.

• Cloning often fails – embryos may not develop properly.

• Shorter life span – cloned animals sometimes age quickly.

• Ethical concerns – people may begin experimenting in how to clone humans

• Animal welfare – surrogate mothers and clones can suffer.

How does natural cloning differ from artificial cloning?

• Natural cloning occurs in asexual reproduction (e.g. bacteria or plants forming runners).

• Artificial cloning is done by humans through techniques like tissue culture, embryo transplants, or adult cell cloning.

Why is lack of variation in clones a problem?

genetic variation gives a species a better chance of survival against disease or environmental changes so the species can adapt

Clones are genetically identical, so a disease that affects one could wipe out all of them.