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