5a (Food production)

Question 1

How can greenhouses increse the yield of crops

Answer 1

Can provide artificial lighting, warmth and CO2. They are limiting factors for photosynthesis. More photosynthesis —> More yield.

Question 2

How can fertilizer increase crop yield

Answer 2

Fertilizers provide mineral ions to the soil. Plants (crops) need these mineral ions for growth. Fertilizers can therefore increase yield.

Question 3

Why are pesticides used

Answer 3

Pesticides eliminate pests that reduce the yield of a crop. Kills fungi, herbs, insects

Question 4

Advantages of pesticides

Answer 4

• Efficient (quick method)
• Immediate effect
• Kills entire population

Question 5

Disadvantages of pesticides

Answer 5

• Can develop resistance
• May kill other organisms
• Toxic to food chain
• Need for continuos application

Question 6

Yeast anaerobic equation

Answer 6

Glucose –> Carbon dioxide + ethanol

Question 7

Yeast in bread production

Answer 7

• While baking, Yeast rapidly uses up all Oxygen present via aerobic respiration
• As a result, anaerobic respiration will occur to produce Carbon Dioxide, which forms bubbles that make the dough rise, and Ethanol, which evaporates into the atmosphere

Question 8

Fermentation

Answer 8

Anaerobic process involving the use of microorganisms - Yeast, Bacteria etc, to commercially produce food products

Question 9

Process of yoghurt

Answer 9

1. Milk is pasteurised (85-95ºC) to kill bacteria in a short period of time
2. Homogenised milk is cooled to 40-45ºC allowing cultured lactobacilius bacteria to be added at optimum temperature
3. Mixture is incubated at this temp for several hours while bacteria digests milk proteins and ferment lactose to lactic acid
4. Thickened yoghurt is stirred and cooled to 5ºC
5. Lastly, flavourings, colourants, and fruits are added prior to packaging

Question 10

Suitable conditions of fermentor

Answer 10

• Aseptic precautions
• Nutrients
• Optimum temp and pH
• Oxygenation
• Agitation

Question 11

Aseptic precautions

Answer 11

Fermenter is steamed to kill Bacteria and prevent chemical contamination, only allowing desired microorganisms

Question 12

Nutrients

Answer 12

Nutrients are needed for organisms to release energy via respiration for growth, allowing metabolic reactions to occur to produce desired product

Question 13

Optimum temp and pH

Answer 13

Temperature and pH probes are used to maintain an optimum environment for enzymes that carry out metabolic process in organisms, allowing organisms to thrive and produce desired product

Question 14

Oxygenation

Answer 14

Oxygen is needed organisms to release energy via aerobic respiration for growth, allowing metabolic reactions to occur to produce desired product

Question 15

Agitation

Answer 15

Agitation by stirring paddles ensure that microorganisms, Nutrients, Oxygen, temperature and pH is evenly distributed

Question 16

Features of industrial fermenters

Answer 16

• Cold water inlet and outlet
• Stirrers
• Temp and pH probes
• Air inlet
• Made of stainless steel

Question 17

Fermenter

Answer 17

Any vessel used to grow microorganisms used for fermentation