Food production IGCSE

Which of these is an example of a biological control?

• Beetles eating aphids which feed on plant leaves

• Foxes eating rabbits

• Using smoke to kill fleas

• Applying herbicides to kill weeds

Give an advantage of using biological controls over pesticides. (multi-select)

• It is cheaper to apply

• You can maintain biodiversity

• You only affect the one organism not others

• Species can become resistant to pesticide

Why do farmers apply pesticides?

• To maintain biodiversity

• To increase yield

• To prevent eutrophication

• To prevent deforestation

Higher temperatures, preventing mineral leaching & ability to raise CO2 levels are benefits of ...

• Deforestation

• Selective breeding

• Greenhouses

• Genetic modification

Higher temperatures increase crop yields in polythene tunnels because ...

• Parasites are at the wrong temperature

• Enzymes work closer to their optimum levels

• Herbivores sweat too much to go in

• It prevents global warming

Yeast, used in beer production, produces which two products from anaerobic respiration?

• Water + oxygen

• Carbon monoxide + ethanol

• Lactic acid

• ethanol + carbon dioxide

You can measure the activity of yeast by:

(multi-select)

• Measuring the volume of gas produced

• Testing with iodine

• how quickly limewater changes colour

• The movement of a bubble along a capillary tube

Which bacterium is used in the manufacture of yoghurt?

• Chlorella

• Mucor

• Lactobacillus

• Pneumococcus

Which reaction is carried out by the bacteria in yoghurt manufacture?

• Glucose --> lactic acid

• Glucose + oxygen --> CO2 + water

• Lipids --> Fatty acids + Glycerol

• Glucose --> Ethanol + CO2

Nitrates are found in fertilisers because plants use them for:

• Transport of materials up the xylem

• forms part of chlorophyll to absorb light

• Active transport of sucrose into the phloem

• producing amino acids and proteins for growth