5A Food Production

Question 1

How can greenhouses and polythene tunnels increase crop yield?

Answer 1

The conditions are kept at the optimum for growth, including the use of artificial lighting and trapping heat from the sun

Question 2

How does increased temperature increase the crop yield

Answer 2

• Enzymes work more efficiently at higher temperatures and reaction rates are faster
• Enzymes are involved in key growth processes and photosynthesis

Question 3

How does a continuous supply of carbon dioxide increase the crop yield?

Answer 3

• CO2 is needed for photosynthesis which is needed to provide energy for growth
• Without a constant supply of enough CO2, it may become a limiting factor and so the rate of photosynthesis is slower

Question 4

How do fertilisers increase crop yield?

Answer 4

Fertilisers provide nutrients for the plant which are needed for growth to make the crops large and give a plentiful yield

Question 5

2 methods of pest control

Answer 5

• Biological control
• Pesticides

Question 6

What is biological control?

Answer 6

It is a method of controlling plant pests by deliberately introducing organisms that feed on the pests to decrease the number of them

Question 7

2 advantages of pesticides

Answer 7

• They are cheap
• They are easy to use

Question 8

3 disadvantages of pesticides

Answer 8

• They are not specific and so can kill other insects that are not pests
• They contaminate water sources
• They have to be applied more than once

Question 9

3 uses of yeast

Answer 9

• Fermentation of alcohol
• Baking (causes bread to rise)
• Making biofuels

Question 10

How does yeast cause bread to rise?

Answer 10

The yeast breaks down the sugars in the bread by respiration and produces carbon dioxide which causes the bread to rise.

Question 11

Describe how yoghurt is made from milk

Answer 11

• Bacteria (Lactobacillus) is used to break the lactose in mil down into lactic acid
• Lactic acid lowers the pH of the milk which causes proteins to denature and makes the milk turn into yoghurt

Question 12

What is a fermenter used for?

Answer 12

To produce large cultures of microorganisms

Question 13

5 things that need to be controlled in an industrial fermenter (TONpC)

Answer 13

• Temperature
• pH
• Nutrient levels
• Oxygen levels
• Contamination

Question 14

Label the diagram of a fermenter

Answer 14

• Gases out
• Nutrients in
• Mixing blades
• Water jacket for temp control
• Products out