Carbon & Nitrogen Cycle (copy)

CARBON CYCLE

Respiration: produces inorganic carbon dioxide from carbohydrates which are broken down to release energy

Excretion, death & decay: living beings remove out carbon-containing compounds

Feeding & Assimilation: pass carbon atoms from carbon dioxide into organic compounds

Photosynthesis: fixes inorganic carbon atoms from carbon dioxide into organic compounds

Fossilisation: if living beings don’t decay fully, fossil fuels are formed

Combustion: when fossil fuels are burned carbon dioxide is released into the atmosphere

Processes/Human Activities that add carbon dioxide to the atmosphere

  • respiration

  • deforestation

  • ploughing

  • combustion of fossil fuels

  • decomposition of microorganisms

NITROGEN CYCLE

Nitrogen is present in proteins, amino acids, vitamins, DNA, RNA, ATP, and chlorophyll. It involves feeding, assimilation, death and decay.

basic cycle

Feeding & Assimilation: nitrogen in organic compounds move along food chains. nitrogen

Decomposition: decomposers produce ammonia from compounds like proteins in animal waste. nitrogen → ammonia

Nitrification: ammonia is oxidised to nitrite, then nitrifying bacteria turn them into nitrates. ammonia → nitrite → nitrate

Active Transport: Plant roots absorb nitrates into proteins. Plants also take up ammonium. nitrates → nitrogen

extra aspects

Denitrification: Denitrifying bacteria use nitrates (for energy) and convert them into nitrogen gas, these bacteria are found in anaerobic conditions. nitrates → nitrogen gas

Nitrogen fixing bacteria (root nodules) : these bacteria convert nitrogen gas into ammonia for amino acids. Nitrogen fixing bacteria contain nitrogenase (enzyme) which catalyses (Nitrogen + Hydrogen → Ammonia). The enzyme needs anaerobic conditions to work. Leghaemoglobin removes oxygen from the nodule. nitrogen gas → ammonia

Lightening: lightning converts nitrogen gas into nitrogen oxides which dissolve in rainwater, entering the soil to be converted into nitrates. nitrogen gas → nitrogen oxides → nitrates

Fertilisers: adding things like ammonium sulfate to soil, but can lead to eutrophication