Use of biological resources
Biotechnology and fermenters
Biotechnology uses living organisms to make useful products. Microorganisms are ideal: they reproduce rapidly, need simple nutrients, and can make complex molecules. Yeast makes ethanol for biofuel and CO₂ to make bread rise. Bacteria make yoghurt (Lactobacillus turns lactose into lactic acid). Enzymes from microbes are used in biological washing powders, pectinase for clearer fruit juice and lactase for lactose-free milk. Industrial fermenters grow microbes in controlled conditions: temperature, pH, oxygen, nutrients, and stirring, kept sterile; penicillin is made this way.
≈ 35 minFood production
Greenhouses and polythene tunnels raise crop yields by controlling limiting factors: higher temperature, extra CO₂ (from paraffin heaters) and artificial light. Fertilisers supply nitrate, phosphate and potassium. Pesticides kill pests but can harm other species and accumulate in food chains; biological control uses a natural predator instead. Fish farming keeps fish in controlled conditions with fed diets and disease control. Monocultures and intensive livestock increase output but reduce biodiversity and can spread disease and pollution.
≈ 35 minGenetic modification
Genetic modification changes an organism's DNA by inserting a gene from another organism. To make human insulin: the gene is cut out with restriction enzymes, leaving sticky ends; a bacterial plasmid is cut with the same enzyme; DNA ligase joins the gene into the plasmid (recombinant plasmid); the plasmid is put into bacteria, which multiply in fermenters and make insulin. GM crops can be pest-resistant, herbicide-resistant or have added nutrients (Golden Rice, vitamin A). Concerns include effects on wild populations and food safety.
≈ 35 min