IGCSE›Cambridge IGCSE Biology›Mind mapsBiotechnologyCambridge IGCSE Biology: Mind mapStudy pack PDFAlso for this subtopic:Revision notesFlashcardsSubtopic testCover factsWhy bacteria?Double every 20 minutes by binary fissionMade in large quantities quickly and cheaplySynthesise complex proteinsFew ethical objectionsCarry plasmidsPlasmidsSmall, circular, double-stranded DNASeparate from the chromosomeCan be cut with restriction enzymesResealed with DNA ligaseReinserted so bacteria express the geneGrowth rateExponential growth of the populationOne bacterium → about 2 million cells in 7 hoursDaughter cells all inherit the plasmidProduction scales exponentiallyBiotechnologybacteria at workEthicsBacteria: no nervous system, no sufferingAnimals: pain and welfare concernsPlants: ecosystem and food chain concernsMolecules madeInsulin from E. coli with the human geneCheaper than pig or cow pancreas extractAntibiotics – yield can be increasedHuman growth hormoneExam tipsLink rapid reproduction to practical outcomesPlasmids are extra DNA, not chromosomalState bacteria have no capacity for sufferingGive insulin steps in order