Flashcards · 0610 · Topic 21

Biotechnology and genetic modification flashcards

15 cards on Topic 21, subtopics 21.1 to 21.3. Pick a subtopic or study them all.

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Why are bacteria useful in biotechnology? (Core): Their rapid reproduction rate and their ability to make complex molecules.
Biotechnology: Using living organisms, usually microorganisms, to make useful products.
Two further reasons bacteria are useful in biotechnology and GM (Extended)Extended: There are few ethical concerns over their manipulation and growth, and they have plasmids, which can carry an inserted gene into bacteria.

Yeast in bread-making vs biofuel production: Both use anaerobic respiration: glucose → alcohol + carbon dioxide. Bread needs the carbon dioxide (bubbles make dough rise). Biofuel needs the ethanol.
Pectinase in fruit juice production: Breaks down pectin in plant cell walls, so more juice is released and the juice is clearer.
Biological washing powders: Contain proteases, lipases and amylases, which digest stains to small soluble molecules, so stains are removed at lower temperatures.
Lactase and lactose-free milkExtended: Lactase breaks down lactose to glucose and galactose, making milk that people who cannot digest lactose can drink.
Products made in fermentersExtended: Insulin (by GM bacteria), penicillin (fungus) and mycoprotein (fungus).
Why is a fermenter cooled, and what else is controlled?Extended: Microbial respiration releases heat, so a water jacket cools it to keep enzymes near the optimum. Also controlled: pH, oxygen (sterile air, paddles), nutrient supply and waste products.

Genetic modification: Changing the genetic material of an organism by removing, changing or inserting individual genes.
Four examples of genetic modification: Human genes inserted into bacteria to make human proteins (e.g. insulin); crop plants given genes for herbicide resistance, for resistance to insect pests, and for improved nutritional qualities.
Restriction enzymes vs DNA ligaseExtended: Restriction enzymes cut DNA at a particular point, leaving sticky ends. DNA ligase joins pieces of DNA together.
Steps in making a human protein in bacteriaExtended: Cut out the gene with restriction enzymes (sticky ends); cut plasmids with the same enzymes; insert the gene and join with DNA ligase (recombinant plasmid); insert into bacteria; bacteria multiply and express the gene.
Why must the plasmid be cut with the same restriction enzyme as the gene?Extended: So the sticky ends are complementary and can pair up.
Advantages and disadvantages of GM cropsExtended: For: higher yields, less insecticide sprayed, weeds killed without harming the crop, better nutrition. Against: costly seed, genes may spread to wild relatives, reduced biodiversity, pests may evolve resistance.