Flashcards
Nitrogen Cycle
Cards in this deck (47)
- 1What % is Nitrogen in the air?78%
- 2What structure is nitrogen?Diatomic
N(triple bond)N - 3What does this structure mean?Nitrogen is stable hence most living organisms are unable to directly use nitrogen gas
- 4What is nitrogen needed for?DNA/ nucleic acid
Amino acids/ proteins
ATP
NADP/NAD
Urea - 5How do plants obtain nitrogen?Absorbing nitrates
- 6How are the nitrates absorbed?Active transport from the soil
- 7What can also be used by some plants?ammonium (NH4+)
- 8How do animals obtain nitrogen?Consuming organic compounds which contain nitrogen
- 9What are the 4 main stages of the nitrogen cycle?Nitrogen fixing
Ammonification
Nitrification
Denitrification - 10What carries out these processes?Bacteria
- 11Chemical formula of NitrogenN2
- 12Chemical formula of NitratesNO3-
- 13Chemical formula of AmmoniaNH3
- 14Chemical formula of AmmoniumNH4+
- 15What is nitrogen fixation?The conversion of nitrogen into nitrogen-containing compounds in green plants
- 16What 4 ways can nitrogen fixation occur?Lightening
Haber Process
Free Living Nitrogen Fixing Bacteria in Soil
Mutualistic Nitrogen Fixing Bacteria in Root Nodules of Legumous Plants - 17How do free-living nitrogen fixing bacteria in soil fix nitrogen?Reduce N2 to ammonia which they use to make organic compounds. These nitrogen rick compounds are released into the soil when they die
- 18How do bacteria in root nodules of legumes fix bacteria?Receive carbohydrate from the plant which receives ammonia from the bacteria in return
- 19What is a mutualistic relationship?Where each organism benefits from the other
- 20What are legumes?Plants such as peas/ beans
- 21In what conditions does this occur?Anaerobic
- 22What is it within the nitrogen fixing bacteria the fixes nitrogen?An enzyme
- 23What is this enzyme?Nitrogenase
- 24What is ammonification?Production of ammonia from nitrogen-containing compounds int eh dead remains of organisms and their faeces and urine
- 25What are examples of these nitrogen containing compounds?Urea
Proteins
Nucleic Acids - 26What is ammonification done by?Saprobionts
- 27What are saprobionts?fungi and bacteria
- 28What is their role?Feed on the nitrogen containing materials, releasing NH3 into the soil
- 29What happens to this NH3?Dissolves in water in the soil to form NH4+
- 30What has happened to nitrogen?Nitrogen has entered the non-living component of the ecosystem
- 31What is nitrification?The conversion of ammonium ions into nitrate ions via nitrogen fixation
- 32What occurs in the first stage?Bacteria oxidises the NH4+ to convert them into nitrite ions NO2-
- 33What occurs in the second stage?Bacteria oxidise nitrite ions to produce NO3- nitrate ions
- 34Is it the same bacteria for both stages?No
different bacteria for different stages - 35What is a feature of the bacteria in the process?Chemoautotrophs
- 36What are chemoautotrophs?Gain energy from the process
- 37What conditions are needed?Aerobic
High oxygen concentration - 38Why do farmers need to plough their fields?Maintain oxygen flow so nitrification can occur, hence increasing nitrates for plant growth
- 39Why do farmers need aerobic conditions?Prevent denitrification - this would decrease nitrates
Support nitrification so more plant growth - 40What do chemoautotrophs do?Use a source of chemical energy to produce food
- 41What does this mean about food chains?Not all food chains start with photosynthesises
- 42What is denitrification?The conversion of soil nitrates into N2
- 43What is this done by?Anaerobic denitrifying bacteria
- 44What conditions does this occur?Anaerobic
- 45What can cause anaerobic conditions?Not ploughing
Waterlogged - 46Why don't farmers want this process?It reduces the number of nitrates in the soil. This are uptake by roots for plant growth
- 47What is the nitrogen cycle? Draw out.
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- Biology A Level (Nutrient Cycles) Flashcards on Nitrogen Cycle, created by Alice Hathaway on 11/11/2017.
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- Alice Hathaway
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