3.5 Food production

Question 1

Fertilisers

Answer 1

They provide chemicals such as nitrates which increase crop yield. The nitrates are dissolved in soil water and are absorbed into plants.

Question 2

Nitrates

Answer 2

They are used to produce amino acids which are synthesised into plant proteins.
Animals consume plants or other animals to obtain amino acids for protein synthesis.

Question 3

Fertilisers can be …

Answer 3

Added to soil to increase the nitrate content of the soil. However fertilisers can leach into fresh water adding extra unwanted nitrates.

Question 4

How many stages are in an algae bloom

Answer 4

FIVE

Question 5

Algae bloom stages

Answer 5

1) Farmer adds fertiliser to fields and excess fertiliser leaches into nearby lochs
2) The algae grows excessively
3) The algae blocks the sun so the plants can’t photosynthesise so they die
4) Bacteria are increasing in numbers due to plants dying
5) Fish die due to bacteria using up all of the oxygen

Question 6

Genetically modified crops

Answer 6

To reduce the use of fertilisers, genetically modified crops can be used. This involves putting the gene from one species into another to gain beneficial characteristics

Question 7

Pesticides

Answer 7

Plants and animals which reduce crop yield can be killer pesticides. Pesticides are sprayed into crops

Question 8

Bioaccumulation

Answer 8

pesticides sprayed onto crops can accumulate in the bodies of organisms over time.
As they are passed along the food chains
toxicity increases and can reach lethal levels.
The build up or toxic substances in living organisms is know as bioaccumulation.

Question 9

Alternatives to pesticides

Answer 9

1) Generically modified plants
2) Biological control - using the natural predator of the pest to reduce numbers