Food Production

Question 1

Describe how you make beer?

Answer 1

1. Barely seeds are germinated. They make amylase to digest starch
2. Seeds are killed and dried to make malt
3. Malt is ground up and mixed with water in a mash tun. Amylase breaks down starch to maltose
4. Mash is boiled and filtered
5. Hops are added for taste and yeast is added to ferment sugars, making beer
6. Beer is centrifuged, filtered and sometimes pasteurised
7. Beer is put into casks or barrels

Question 2

How is yoghurt made?

Answer 2

• Equipment sterilised to kill off any unwanted microorganisms
  1. Milk pasteurised at 85-95 degrees Celsius for 15-30 minutes to kill any bacteria
  2. Milk is homogenised
  3. Milk is cooled to 40-45 degrees Celsius and inoculated with a starter culture of lactic acid bacteria (lactobacillus)
  4. Mixture is incubated at this temperature for several hours (in fermenter), while bacteria digest milk proteins and ferment lactose to lactic acid
• The bacteria ferment the lactose sugar in the milk to form lactic acid (lactose –> lactic acid)
• The acid produced causes the pH to drop and this causes the milk to coagulate
• The decrease in pH also prevents to growth of other microorganisms, thus preserving the nutrients of the milk 5. Thickened yoghurt is stirred and cooled to 5 degrees Celsius (leave in fridge to stop bacteria from over reproducing)
  6. Flavourings, colorants and fruit may be added before packaging

Question 3

How can glasshouses and polythene tunnels be used to increase the yield of crops?

Answer 3

1. They can increase the rate of photosynthesis and so increase crop yields
2. The glass or polythene gives a ‘greenhouse’ effect, warming up the growing area so that photosynthesis can take place as fast as possible to increase the yield
3. The levels of carbon dioxide in the air can also be controlled to speed up the rate of photosynthesis e.g. by using a paraffin heater to heat the place, and as the paraffin burns it makes carbon dioxide as a by-product
4. This also keeps them free from pests and diseases
5. Farmers can also supply artificial light after the sun goes down to give their plants more time to photosynthesis and they can use a heater in the winter to help keep the temperature at the ideal level

Question 4

How can fertiliser be used to increase crop yield?

Answer 4

1. Fertilisers return nitrates and other minerals to the soil, or provide more of them to make sure that plants have all the nutrients they need to grow as quickly as possible and this helps to increase the crop yield e.g. these elements could be missing as they have been used by a previous crop
2. This is because plants need certain elements e.g. nitrogen, potassium and phosphorus, so they can make important compounds like proteins and if plants do not get enough of these elements, their growth and life processes are affected

Question 5

Why is pest control used?

Answer 5

1. Pests include microorganisms, insects and mammals (e.g. rats)
2. Pests are controlled to prevent them damaging crops and so and pests that feed on crops are killed using various methods of pest control. This means fewer plants are damaged or destroyed, increasing crop yield
3. Pesticides are a form of chemical pest control and are the most widely used way of controlling pests
4. These are chemicals that farmers spray on their crops to kill the pests. They are very effective

Question 6

What are the negatives to using pest control?

Answer 6

1. They are often poisonous to humans, so they must be sued carefully to keep the amount of pesticide in food below a safe level
2. Some pesticides also harm other wildlife
3. They are expensive
4. Pests can become resistant to them
5. Pesticides can cause environmental damage
6. They can also kill useful animals such as pollinating insects and the predators of the pests

Question 7

What is biological pest control?

Answer 7

• Another organism to control a pest, either by encouraging wild organisms or adding new ones
• The helpful organisms, could be predators, parasites, or disease-causing

Question 8

What are the advantages and disadvantages of biological control?

Answer 8

1. Advantages:
   - They can have a long-lasting effect than spraying pesticides
   - Less harmful to wildlife than spraying pesticides
   - It can be very effective
   - It reduces the numbers to a level where they are not causing significant crop damage
2. Disadvantages:
   - Introducing new organisms can have problems e.g. can toads were introduced to Australia to eat beetles, but they are now a major pest themselves because they poison the native species and eat them
   - It never completely gets rid of the pest

Question 9

What is pollution?

Answer 9

Pollution means releasing substances into the environment in quantities that cause harmful effects. We pollute the air with many gases

Question 10

Describe a simple experiment to investigate carbon dioxide production by yeast, in different conditions

Answer 10

1. Mix together some sugar, yeast, and distilled water and then add the mixture to a test tube
2. Attach a bung with a tube leading to a second test tube of water
3. Place the tube containing the yeast mixture in a water bath at a certain temperature
4. Leave the tube to warm up a bit and then count how many bubbles are produced in a given period of time (e.g. one minute)
5. Use this to calculate the rate of CO2 production, which gives an indication of respiration rate
6. Repeat the experiment with the water bath set at different temperatures
7. Respiration is controlled by enzymes, so as temperature increases, so should the rate of respiration, until the optimum temperature
   -The example looks at how temperature affects the rate, but the basic idea would be the same whatever the variable you were investigating. For example you could vary the concentration of sugar (but keep the temperature of the water bath the same)
   You could also alter the experiment to give more accurate results by replacing the second tube with a gas syringe and you would measure the volume of gas produced

Question 11

What is biotechnology?

Answer 11

The use of living organisms to make useful chemicals and products or to perform an industrial task

Question 12

What is the role of yeast in beer production?

Answer 12

-When yeast respires anaerobically it produces ethanol, the chemical which acts as a drug in alcoholic drinks, the carbon dioxide produced by the yeast is also used to make bread rise
-Yeast produces carbon dioxide as a waste product of respiration
Glucose–>ethanol+carbon dioxide

Question 13

Describe fermenters

Answer 13

• These are huge containers that hold up to 200,000 dm cubed if liquid
• They make it possible to control the environmental conditions such as temperature, oxygen and carbon dioxide concentrations, pH and nutrient levels so that the microorganisms can grow and respire without being limited and can work as efficiently as possible

Question 14

Why is it important that the inside of a fermenter is sterile?

Answer 14

So that only the microorganisms that are wanted grow in the culture. Penicillin, a widely used antibiotic is made in an industrial fermenter using Penicillium, mould

Question 15

What are the advantages of using yoghurt over milk?

Answer 15

1. Lasts longer

2. Lactose intolerant can eat?

Question 16

Why is the pH in the fermenter kept constant?

Answer 16

1. Kept at optimum level for the microorganisms’ enzymes to work efficiently. This keeps the rate of reaction and product yield as high as possible
2. It is kept constant by adding acid or alkali

Question 17

What is the point of the water jacket?

Answer 17

1. The temperature is also monitored and kept at an optimum level
2. The water cooled jacket makes sure it does not get too hot that the enzymes denature

Question 18

Why are the microorganisms mixed with nutrients?

Answer 18

1. This stops them sinking to the bottom, and helps keep the temperature even through the fermenter
2. Nutrients are needed by the microorganisms for growth are provided in the liquid culture medium
3. Microorganisms are kept in contact with fresh medium by paddles that circulate (or agitate) the medium around the vessel
4. This increases the product yield because the microorganisms can always access the nutrients needed for growth

Question 19

What is the point of the air inlet?

Answer 19

1. Filtered air is added when microorganisms need oxygen
2. If the microorganisms need oxygen for respiration, it is added by pumping in sterile air
3. This increases the product yield because microorganisms can always respire to provide the energy for growth

Question 20

What and why is the fermenter made of?

Answer 20

1. Some microorganisms produce acid wastes, so the fermenter is made of a meta that will not corrode such as stainless steel

Question 21

How are the vessels sterilised?

Answer 21

1. Vessels are sterilised between uses with superheated steam that kills unwanted microbes
2. Having aseptic conditions increases the product yield because the microorganisms are not competing with other organisms
3. It also means that the product does not get contaminated

Question 22

How is the contents of the fermenter monitored?

Answer 22

1. The contents of the fermenter are monitored by special probes
2. These record the concentration of nutrients, temperature, pH, oxygen and carbon dioxide levels
3. The data is fed into a computer, which automatically controls the conditions in the fermenter

Question 23

Describe one way in which fish are farmed, what are the conditions like?

Answer 23

• Fish can be kept in cages in the sea, e.g. salmon farming in Scotland
  1. This stops them using as much energy swimming about
  2. The cages also protects them from interspecific predation (being eaten by other animals like birds or seals)
  3. They are fed of a diet of food pellets that is carefully controlled to maximise the amount of energy they get, the better the quality the food is, the quicker and bigger the fish will grow
  4. Young fish are reared in special tanks to ensure that as many survive as possible
  5. Fish are selectively bred to produce less aggressive, faster-growing fish

Question 24

Why is there fish farming?

Answer 24

More and more fish are being farmed to increase the amount of protein food available

Question 25

Why is it important to keep younger fish in separate tanks from bigger and older fish?

Answer 25

1. To provide regular food and avoid too much competition between member of the same species
2. To avoid intraspecific predation (where organisms eat individuals of the same species), so the big fish do not eat the little ones

Question 26

What is the negative effect of keeping fish farmed in cages in the sea?

Answer 26

1. Fish kept in cages are more prone to disease and parasites
2. One pest is sea lice, which can be treated with pesticides which kill them
3. To avoid pollution from chemical pesticides, biological pest control can be used instead e.g. a small fish called a wrasse eats the lice off the backs of salmon in salmon farming in Scotland

Question 27

Describe how fish can be farmed in tanks?

Answer 27

• Freshwater fish, e.g. carp, can be farmed in ponds or indoors in tanks where conditions can be controlled, this is especially useful for controlling the water quality
  1. The water can be monitored to check the temperature, pH and oxygen level is ok
  2. It is easy to control how much food is supplied and give exactly the right sort of food
  3. The water can be removed and filtered to get rid of waste food and fish poo, this keeps the water clean for the fish and avoid pollution wherever the water ends up

Question 28

What are the negative impacts of fish farming?

Answer 28

1. Disease can spread quickly and the waste form fish and the excess food can cause water pollution, including eutrophication
2. Wild fish stocks are being depleted to make the pellets that are fed to farmed fish

Question 29

What is fish farming?

Answer 29

When large numbers of fish are kept in freshwater or seawater tanks and enclosures