21.1Biotechnology and Genetic Modification

Biotechnology and genetic modification — Cambridge IGCSE Biology 0610 Revision Notes & Topical Questions

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📚 Cambridge IGCSE Biology 0610 Hub / Topical Revision

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Lesson summary

21.1 Biotechnology and genetic modification — IGCSE BIOLOGY notes: Describe why bacteria are useful, everyday uses of biotechnology, fermenters and mycoprotein, and genetic modification of bacteria and crops.Biotechnology = the use of living organisms, especially microorganisms, …

Complex molecules
Rapid reproduction
Genetic code
Anaerobic respiration
Biofuel steps
Biological washing powders

Part 1 of 10Why bacteria are useful

Biotechnology

Biotechnology the use of living organisms, especially microorganisms, or their enzymes to make useful products.

Complex molecules

Complex molecules certain bacteria added to milk make enzymes that turn it into yoghurt.

Rapid reproduction

Rapid reproduction the amount of product increases quickly.

Ethics

Ethics few ethical concerns about growing them in large numbers.

Plasmids

Plasmids an ideal way to transfer DNA between cells in genetic modification.

Genetic code

Genetic code bacteria share the universal genetic code, so they can read a human gene and make the same protein.

Part 2 of 10Yeast: biofuels and bread

1Anaerobic respiration

Anaerobic respiration yeast uses sugar and produces ethanol and carbon dioxide.

2Biofuel steps

Biofuel steps break plant material into pieces and mix with yeast, yeast respires anaerobically to make ethanol, separate the liquid and remove water,
then blend the ethanol with petrol or use it alone.

3Crop use

Crop use waste parts of crops can be used, but crops grown for ethanol may reduce land for food.

4Bread

Bread yeast mixed with flour and water respires anaerobically, and the carbon dioxide trapped in the dough makes it rise.

Part 3 of 10Fruit juice and washing powders

1Pectinase

Pectinase breaks down pectin in plant cell walls, so cell walls break more easily.

2Juice

Juice more juice is released and it is clearer because large polysaccharides are broken down.

3Biological washing powders

Biological washing powders contain enzymes that break down fats and proteins into small soluble molecules.

4Advantages

Advantages work at lower temperatures, saving energy, and suit delicate fabrics.

Part 4 of 10Lactose-free milk and penicillin

Lactose intolerance

Lactose intolerance many people lose lactase as they get older, causing nausea, flatulence and diarrhoea after milk.

Lactose-free milk

Lactose-free milk lactase is added to milk to break down the lactose.

Penicillin

Penicillin the first antibiotic, discovered in 1928 by Alexander Fleming from the Penicillium mould, which kills certain bacteria.

Production

Production now made on a large scale in industrial fermenters.

Part 5 of 10Industrial fermenters

Industrial fermenter with temperature control, air supply and stirring

Condition	How it is controlled
Aseptic precautions	Cleaned with steam to kill unwanted microorganisms
Nutrients	Supplied for respiration, growth and reproduction
Optimum temperature	Monitored by probes and kept using a water jacket
Optimum pH	Monitored by a probe and adjusted with acids and alkalis
Oxygenation	Oxygen supplied for aerobic respiration
Agitation	Stirring paddles distribute temperature, pH, nutrients and oxygen evenly
Waste	Contents are filtered to remove waste products

Part 6 of 10Mycoprotein

The fungus Fusarium is cultured in large fermenters at optimum pH and temperature.

It is grown in aerobic conditions with glucose syrup as food.

The fungus grows and multiplies.

The fungal biomass is harvested and purified.

Mycoprotein
- a protein-rich food suitable for vegetarians, used in Quorn products.

Part 7 of 10Genetic modification

Genetic modification

Genetic modification changing the genetic material of an organism by removing, changing or inserting individual genes from another organism.

Transgenic organism

Transgenic organism the organism receiving the gene.

Recombinant DNA

DNA containing DNA from another organism.

Examples

Examples insulin

the human insulin gene is inserted into bacteria, which make insulin for diabetics.

Examples

Examples crops

soya, maize and rice carry a bacterial gene for an insect-killing poison, or herbicide resistance.

Golden rice

Golden rice has genes giving a chemical converted to vitamin A, helping prevent deficiency diseases.

Part 8 of 10Making a human protein in bacteria

Locate the human gene, for example for insulin.

Cut it out with restriction enzymes, leaving sticky ends.

Cut a bacterial plasmid with the same enzyme, giving matching sticky ends.

Join the gene and plasmid with DNA ligase.

Insert the recombinant plasmid into a bacterial cell.

The bacteria reproduce, copying the plasmid, and all make the human protein.

Grow the bacteria in a fermenter in controlled conditions to make large quantities.

Part 9 of 10GM crops

Advantages	Disadvantages
Less use of herbicides and pesticides	Higher seed costs, which can disadvantage poorer farmers
Cheaper and less time-consuming for farmers	Greater dependence on certain chemicals
Higher yields as crops face less competition and pest damage	Inserted genes may spread to wild plants by pollination
	Reduced biodiversity, affecting insects and insect-eating birds
	Some GM plants grow less well than non-GM plants

Part 10 of 10More from the specification

Genetically modified
- Having had genes from another organism inserted.

Key terms

Term	Meaning
Biotechnology	Use of organisms or their enzymes to make useful products.
Fermenter	A container for growing microorganisms in large amounts.
Mycoprotein	Protein-rich food made from the fungus Fusarium.
Genetic modification	Changing an organism's genes by inserting, removing or altering them.
Plasmid	A circle of DNA in a bacterial cell used as a vector.
Restriction enzyme	An enzyme that cuts DNA at specific sequences, leaving sticky ends.
DNA ligase	An enzyme that joins pieces of DNA.
Transgenic	Containing a gene from another organism.

Avoid these mistakes

Saying bacteria are used only because they are small — they reproduce rapidly, make complex molecules and have plasmids.

Saying yeast in bread respires aerobically only — it respires anaerobically and carbon dioxide raises the dough.

Mixing up restriction enzymes and ligase — restriction enzymes cut DNA and ligase joins it.

Saying GM crops have no risks — gene transfer, cost and biodiversity are concerns.

Last updated: 24 October 2026