21.3 Genetic modification

GENETIC MODIFICATION = changing an organism's DNA by REMOVING, CHANGING or INSERTING individual genes. 4 named examples: (a) human genes inserted into bacteria → human proteins (e.g. insulin in E. coli); (b) genes inserted into crops → herbicide resistance; (c) genes inserted into crops → insect-pest resistance (Bt); (d) genes inserted into crops → improved nutritional quality (e.g. golden rice + vitamin A). HL extension: 6-step recombinant-DNA workflow — RESTRICTION ENZYMES cut human DNA forming STICKY ENDS; same enzyme cuts bacterial PLASMID forming complementary sticky ends; DNA LIGASE seals the join → RECOMBINANT PLASMID; plasmid into bacterium; bacteria multiply; expression → human protein. HL discussion of GM crop advantages (higher yields, less spraying, better nutrition) and disadvantages (gene escape via pollen, biodiversity loss, pest resistance, ethics + corporate control of patented seeds), with examples from soya, maize and rice.