3.5

Question 1

Nitrates in ecosystems

Answer 1

Nitrates found in fertilisers dissolve into the soil water and are absorbed into plants via the roots

Nitrates produce amino acids which are synthesised into plant proteins

Question 2

Pesticide

Answer 2

Substance used to prevent\destroy pests which can decrease yield of a plant

Question 3

Types of pesticide

Answer 3

Insecticide -kills insect
Herbicide -kills plants
Fungicides -kill fungi

Question 4

Problems which pesticides

Answer 4

Can have unintended effect on other populations
Can acccumulate in bodies of organisms over time
When past along food chains toxicity increases can reach lethal levels
This is called bioaccumulation

Question 5

Gm crops can

Answer 5

Increase food yield
Reduce use of fertilisers
Reduce use of pesticides

Question 6

Biological control

Answer 6

Using organisms such as natural predators or parasites to control pest numbers

Alternative to pesticides

Question 7

Organisms used in biological control

Answer 7

Lady birds
Viruses
Caterpillar moths