Biotechnology and genetic modification flashcards

Topic 18: Biotechnology and genetic modification

Biotechnology (O Level)

Using living organisms, or their enzymes, to make useful products.

Yeast in bread vs ethanol production

Both use anaerobic respiration: glucose → ethanol + carbon dioxide. Bread uses the carbon dioxide (bubbles make dough rise; most ethanol evaporates in baking). Ethanol production uses the ethanol, for drinks or fuel.

Four reasons bacteria are useful in biotechnology

Rapid reproduction rate; they make complex molecules (e.g. human insulin); no ethical concerns over their manipulation and growth; plasmids, into which a gene can be inserted.

A bacterium divides every 20 minutes. How many cells from one cell in 80 minutes?

80 ÷ 20 = 4 divisions; 2⁴ = 16 cells.

Five conditions controlled in a fermenter

Temperature (cooling water jacket: respiration releases heat), pH (probe, add acid or alkali), oxygen (sterile air, paddles), nutrient supply, and removal of waste products.

Enzymes in washing powder, fruit juice and lactose-free milk

Washing powder: proteases and lipases digest stains at lower temperatures. Fruit juice: pectinase breaks down pectin in cell walls, giving more and clearer juice. Lactase: lactose → glucose + galactose.

Genetic modification (O Level)

Changing the genetic material of an organism by removing, changing or inserting individual genes.

How GM bacteria produce human insulin

The gene for human insulin is inserted into bacterial DNA. The bacteria multiply in fermenters and make human insulin, which is extracted for people with diabetes.

Three reasons genes are inserted into crop plants

Resistance to herbicides, resistance to insect pests, and additional vitamins (e.g. Golden Rice makes beta-carotene, converted to vitamin A).

Advantages and risks of GM crops

Advantages: higher yields, less insecticide used, more nutritious crops. Risks: genes spread to wild relatives by pollen, pests become resistant to the toxin, non-pest insects harmed, seed costs for farmers.