LEARNING OBJECTIVES
What you will be able to do
- explain bacterial usefulness
- describe yeast and enzyme uses
- explain fermenter control
- outline genetic modification
- evaluate GM crops
AT A GLANCE
INTRODUCTION · THE BIG IDEA
How microorganisms, enzymes and recombinant DNA produce useful materials.
Microorganisms grow quickly and can make useful enzymes, foods, medicines and fuels. Industrial production depends on maintaining conditions that maximise yield without contamination.
Genetic modification adds a DNA-level tool: selected genes can be inserted into cells, expressed as proteins and evaluated for benefits and risks.
SECTION 01
Microorganisms and enzymes
Bacteria reproduce rapidly, make complex molecules and contain plasmids; their manipulation raises fewer ethical concerns than many animals.
DETAILED EXPLANATION
- Pectinase breaks down pectin, increasing juice yield and clarity.
- Washing-powder proteases, lipases and amylases digest protein, fat and starch stains.
- To compare biological washing powders, use equal stained samples, equal detergent volumes and the same washing time. Change temperature only, repeat the test and compare stain removal.
- Lactase breaks lactose into simpler sugars to produce lactose-free milk.
SECTION 02
Fermenters
Industrial fermenters grow microorganisms to make insulin, penicillin, mycoprotein and other products.
DETAILED EXPLANATION
- Supply nutrients and suitable oxygen; mixing distributes materials and heat.
- Cooling removes respiratory heat; sterile equipment prevents contamination; waste is removed.
SECTION 03
Genetic modification
Genetic modification removes, changes or inserts individual genes. A plasmid can carry a human gene and direct bacteria to make its protein.
DETAILED EXPLANATION
- DNA ligase joins them into a recombinant plasmid.
- The plasmid enters bacteria, which multiply and express the gene.
- Uses include human proteins and crops with herbicide resistance, insect resistance or improved nutrition.
SECTION 04
GM crop evaluation
Benefits may include yield, nutrition and pest control with less insecticide. Concerns include gene flow, resistant pests, non-target effects, reduced diversity, seed cost and dependence on suppliers.
STEP-BY-STEP EXAM EXAMPLE
Outlining recombinant insulin production
- Use a restriction enzyme to cut out the human insulin gene and open a bacterial plasmid.
- Join the matching ends with DNA ligase to form a recombinant plasmid.
- Insert the plasmid into a bacterium and select transformed cells.
- Grow the bacteria in controlled fermenters, then harvest and purify the insulin.
Answer: A human gene in a bacterial plasmid directs bacteria to make human insulin.
QUICK CHAPTER SUMMARY
The ideas to carry forward
- Microorganisms support biotechnology.
- Fermenters control growth.
- Restriction enzymes and ligase make recombinant plasmids.
- Modified genes produce proteins or crop traits.
- GM decisions balance evidence and context.
QUICK REVISION CHECKLIST
Can you do each of these without your notes?
- explain bacterial usefulness
- describe yeast and enzyme uses
- explain fermenter control
- outline genetic modification
- evaluate GM crops