Food Production

Question 1

Describe the steps taken to select a particular feature in an organism.

Answer 1

1. choose individuals with the desired feature
2. let only these individuals reproduce
3. choose the offspring that have the desired feature
4. let only these individuals reproduce
5. repeat steps 3 and 4 until you have produced a variety in which all the individuals show the desired feature

Question 2

What are the benefits of greenhouses for farmers?

Answer 2

artificial heating
artificial lighting
additional carbon dioxide in the air
regular watering

Question 3

Why is glass a good roof?

Answer 3

Natural light in for photosynthesis during the summer. Additional lighting gives a ‘longer day’ during the winter for valuable crops.

Question 4

What is an organic fertiliser?

Answer 4

Made from the faeces of a range of animals, sometimes mixed with straw. Also compost from legumes such as a clover.

Question 5

What is an inorganic fertiliser?

Answer 5

Inorganic compounds carefully formulated to yield a specific concentration of a particular ion when applied according to the manufacturer’s instructions.

Question 6

What are the advantages of organic fertilisers?

Answer 6

Improve soil structure
Greater range of minerals
releases minerals over a longer period of time
less cost to farmer as it is already available on the farm

Question 7

What are the disadvantages of organic fertilisers?

Answer 7

Slow acting - has to be decomposed first
Bulkier, so more difficult than inorganic fertilisers to apply
May contain pests

Question 8

What are the advantages of inorganic fertilisers?

Answer 8

Mineral ions to release immediately so fast acting
Contents known
Easy to apply

Question 9

What are the disadvantages of inorganic fertilisers?

Answer 9

Can lead to eutrophication as fertiliser is soluble
Requires regular reapplication

Question 10

What is another way to replace lost nitrates?

Answer 10

They could grow a legume crop such as a clover in a field one year in four. These plants have nitrogen fixing bacteria in nodules on their roots.
They convert nitrogen gas in the air into ammonium ions
Some of this is passed to the plants which use it to make proteins

Question 11

What are pests?

Answer 11

organisms that reduce the yield of crop plants or stock animals

Question 12

How can pests be controlled?

Answer 12

Pesticides
Biological control

Question 13

How do pesticides damage ecosystems?

Answer 13

The pesticide molecules are often passed up the food chain becoming concentrated in the tissues of top carnivores

Question 14

What is biological control?

Answer 14

The aim is to reduce pest numbers to a level where they no longer cause significant economic damage.

Question 15

What are the advantages of pesticides?

Answer 15

Reduces pest population instantly
Can kill the whole population of pests

Question 16

What are the disadvantages of pesticides?

Answer 16

Cost
Not specific e.g. will kill predaceous insects and pollinating insects addition to the pest.
Pest can become resistant to chemical
Chemical can concentrate in all organisms higher up the food chain

Question 17

What are the advantages of biological control?

Answer 17

Organism only introduced once as it will reproduce
Only one cost for initial introduction
Pest specific - only kills the pest
Pest will not become resistant
No effect on other animals in the food chain

Question 18

What are the disadvantages of biological control?

Answer 18

Takes time to reduce pest population
Not all population killed
Expensive if re-populating is required

Question 19

What happens with ethanol in bread making?

Answer 19

Ethanol evaporates as there are high temperatures used in bread making.

Question 20

What helps the bread to rise?

Answer 20

Bubbles of carbon dioxide gas expand the dough

Question 21

What is the anaerobic equation for respiration?

Answer 21

glucose –> ethanol + carbon dioxide

Question 22

What is the function of the cooling jacket in an industrial fermenter?

Answer 22

Removes heat energy, stopping the fermenter overheating and enzymes denaturing.

Question 23

What is the function of the air filter in an industrial fermenter?

Answer 23

Filters air coming in, maintaining sterile conditions.

Question 24

What is the function of the stirrers in an industrial fermenter?

Answer 24

Keep the broth well stirred to oxygenate all parts of the fermenter and prevent micro-organisms setting.

Question 25

What is the purpose of a growth medium in an industrial fermenter?

Answer 25

Contains all necessary glucose and amino acids for micro-organisms.

Question 26

What is the purpose of super heated steam in an industrial fermenter?

Answer 26

Applied before the fermenter is used, killing unwanted micro-organisms. Leaves only water with no other residue.

Question 27

What bacteria is used in yoghurt production?

Answer 27

Lactobacillus bulgaricus

Question 28

Describe the method for yoghurt production.

Answer 28

The equipment is sterilised
The milk is pasteurised by heating
The bacterial culture is added to the cooled milk and left 46 degrees for about 4 hours.
Then the yoghurt is cooled to 5 degrees to help preserve the yoghurt
Samples are taken to see if the yoghurt is ready
Flavours and colours are added then the yoghurt is packaged

Question 29

Lactobacillus respires anaerobically producing lactic acid. What is the effect of this?

Answer 29

This lowers the pH, acting as a preservative. The acid also coagulates the milk protein, as the acidic conditions change the shape of the proteins, giving yoghurt its texture and flavour.

Question 30

Why do farmers feed fish a high lipid and protein food?

Answer 30

To promote rapid growth

Question 31

What are problems with putting several species in one pond?

Answer 31

Interspecific competition: different species will compete for food and some species may be wiped out
Predation: carnivorous species will prey on other fish.

Question 32

What are solutions to predation?

Answer 32

Placing a cover over the pond to reduce predation from birds

Question 33

What are solutions to interspecific competition?

Answer 33

Place different species in different ponds. Use nets to separate species and wild/ farmed populations.

Question 34

What are problems of putting too many individuals in one pond?

Answer 34

Intraspecific competition: Larger individuals will out-compete smaller individuals for food or larger individuals may prey on smaller individuals.
Infectious diseases: parasites and pathogens spread quickly if the fish are too close together

Question 35

What is a solution to problems with having too many fish in one pond?

Answer 35

Separate fish by age and size. Remove dead or infected fish quickly and add antibiotics in the water to kill bacteria. Add antifungals or chemicals to kill parasites.

Question 36

How do fish farms affect the environment?

Answer 36

Fish may escape and out-compete or interbreed with local species reducing biodiversity and upsetting the local ecosystem
Parasites or pathogens can be introduced into ecosystems by farmed fish
Excess feed and waste from fish can cause eutrophication and a reduction in oxygen concentrations in the water.