1. They feed on dead matter
Suggest one way in which microorganisms are involved in recycling phosphorus contained in the tissues of dead carnivores.
They feed on dead matter
Secreting enzymes and absorbing the products of digestion
Which are used to produce new compounds such as ATP and nucleic acids

2. Nitrate is converted to nitrogen gas By denitrifying bacteria
Explain how each of biological denitrification could account for falling nitrate concentration.
Nitrate is converted to nitrogen gas
By denitrifying bacteria
The nitrogen gas is released into the atmosphere

3. Feed on leaf litter and increase its surface area
Describe how nitrogen in compounds in a dead plant is made available for use by other plants.
Detritivores
Feed on leaf litter and increase its surface area
Microbial saprophytes
Secrete enzymes and absorb amino acids
Which they deaminate releasing ammonia
Nitrifying bacteria
Convert ammonia to nitrite and then nitrate
Which is absorbed by plant roots
And transported through the xylem
To be incorporated into amino acids

4. Nitrogen fixing bacteria in clover roots
Explain why a mixture of ryegrass and clover has a higher yield than ryegrass alone.
Nitrogen fixing bacteria in clover roots
Convert nitrogen gas into ammonia compounds
Which can be used by the clover plants to make amino acids
Saprophytic bacteria
Digest dead matter from the clover plants and release ammonia
Nitrifying bacteria in the soil
Convert the ammonia to nitrite and then nitrite
Which the grass plants absorb and use to make amino acids for their growth

5. Feed on dead material and increase its surface area
Nitrogen-fixing bacteria are described as providing “the first vital steps in making atmospheric nitrogen available to other living organisms”. Describe the role of microorganisms in making nitrogen in organic compounds in dead material from leguminous plants available to other plants.
Detritivores
Feed on dead material and increase its surface area
Microbial saprophytes
Secrete enzymes and absorb amino acids
Which they deaminate, releasing ammonia
Nitrifying bacteria
Convert ammonia to nitrite and then nitrate
Which is absorbed by plant roots
And transported through the xylem
To be incorporated into amino acids

6. heterotrophic nutrition deamination nitrification respiration
photosynthesis
denitrification
heterotrophic nutrition
deamination
nitrification
respiration
nitrogen fixation
combustion
saprophytic nutrition
autotrophic nutrition
death and excretion

7. Feed on leaf litter and increase its surface area by excreting wastes
Some of the carbon from carbon compounds in leaf litter is eventually incorporated into carbon compounds in newly grown leaves. Suggest what living processes might be involved in the recycling of carbon and describe the contribution each makes to the recycling.
Detritivores
Feed on leaf litter and increase its surface area by excreting wastes
Microbial saprophytes
Secrete enzymes and absorb products
Releasing carbon dioxide from respiration
Absorbed through stomata of mature leaves
Photosynthesis produces glucose
Which is transported as sucrose in phloem
To new leaves where used to make cellulose and amino acids

8. They feed on dead matter Digesting part of it in their guts
Describe how detritivores are involved in the recycling of nutrients.
They feed on dead matter
Digesting part of it in their guts
Faeces contains undigested waste with a larger surface area
Increasing the decomposition of dead matter by saprophytic micobes

9. Describe how the carbohydrates in the dead leaves in the beech wood would be recycled by the activity of detritivores and microorganisms.
Explain how digestion of insects helps the sundew to obtain additional nitrogen compounds.