Food Production

Question 1

how can glasshouses and polytunnels increase crop yield?

Answer 1

1. free from pests
2. traps suns heat/use heaters for warmth
3. farmers can supply artificial light

Question 2

how does increased CO2 and temp increase crop yields?

Answer 2

Paraffin heaters- increase CO2 and temp levels

1. by increasing CO2 and temp levels as well as amount of light, a farmer can increase rate of photosynthesis.
2. this means plants will grow bigger and faster = crop yields higher

Question 3

how can fertilisers be used to increase crop yield?

Answer 3

farmers use fertilisers to replace missing minerals or provide more of them. this increases crop yield.

Question 4

what are the advantages and disadvantages of using pesticides for pest control?

Answer 4

ADVANTAGES:

1. faster
2. effective

DISADVANTAGES:

1. expensive
2. damages other wildlife
3. may become resistant

Question 5

what are the advantages and disadvantages of using biological control for pest control?

Answer 5

ADVANTAGES:

1. longer lasting effect
2. less harmful to wildlife

DISADVANTAGES:

1. reduces population but doesn’t completely remove pest
2. sometimes control becomes pest (cane toads)

Question 6

how does yeast help bread rise?

Answer 6

1. enzymes break down carbohydrates in flour into sugars
2. yeast then uses these sugars in aerobic respiration producing carbon dioxide
3. when the oxygen runs out the yeast switches to anaerobic = fermentation (CO2 and alcohol)
4. CO2 produced is trapped in bubbles in the dough
5. these pockets of gas expand causing the bread to rise.
6. the bread is then baked. yeast continues to ferment until the temp of the dough kills the yeast.

Question 7

what is the role of bacteria in yogurt production?

Answer 7

1. sterilise equipment to kill any unwanted microorganisms
2. milk is pasteurised to kill any unwanted microorganisms. then it’s cooled
3. LACTOBACILLUS bacteria are added and the mixture is heated to about 40°C in a fermenter
4. the bacteria ferment the lactose sugar in the milk to form lactic acid.
5. lactic acid causes the milk to clot and solidify into yoghurt
6. flavours are added

Question 8

how are industrial fermenters used?

Answer 8

1. NUTRIENTS- provided in the liquid culture medium for growth
2. pH- monitored and kept at optimum for enzymes to work efficiently (ROR and product yield high)
3. TEMPERATURE- monitored and kept at optimum level. water cooler jacket = not too hot and enzymes don’t denature.
4. PADDLES- microorganisms kept in contact with fresh medium by paddles that circulate medium around the vessel.
5. OXYGEN- if microorganisms need oxygen for respiration it’s added by pumping in sterile air.
6. STERILISATION- vessel sterilised inbetween uses to kill unwanted microbes = aseptic conditions

Question 9

Fish farming in CAGES

Answer 9

kept in cages in the sea.
ADVANTAGES:
1. stop using as much energy swimming around
2. protects from interspecific predation
3. fed a diet of food pellets carefully controlled to maximise amount of entry get. (quicker and bigger the fish will grow)
4. young fish in separate cages = prevent intraspecific predation
5. fish can be selectively bred to produce less aggressive, larger fish.
DISADVANTAGES:
6. fish in cages more prone to disease. killed by pesticides or biological control.

Question 10

Fish farming in TANKS

Answer 10

1. water can be monitored to check temp, pH and oxygen levels are OK.
2. easy to control amount of food supplied and give exactly right sort of food.
3. water can be removed and filtered to get rid of waste food and poo = avoids pollution.