Flashcards
6.3.1 Nitrogen cycle
Cards in this deck (9)
- 1What are the three ways nitrogen fixation can occur?-Lightning strike
-Haber process (high pressure and heat in industry)
-Nitrogen fixing bacteria - 2Give the name of the nitrogen fixing bacteria in soilAzotobacter
- 3Describe what Azotobacter doesFixes N gas from the air spaces in the soil an makes amino acids from it to grow. When they die, they add their nitrates to the soil
- 4Give the name of the nitrogen fixing bacteria found in root nodules and state which plants they are found inRhizobium found in legumin plants such as peas and beans
- 5Explain how Rhizobium worksLeyhaemoglobin in plant nodes absorb oxygen and keep conditions anaerobic , allowing bacteria to use nitrogen reductase (enzyme) to reduce nitrogen gas to ammonium ions that the plant can use, in exchange for glucose.
- 6Describe how ammonification worksSaprotrophic bacteria and fungi break down proteins of dead organisms into ammonia, then ammonium ions
- 7Describe how nitrification worksAmmonium compounds are oxidised into nitrites (nitrosomonas bacteria) then oxidised to nitrates (nitrobacter) in well oxygenated soil as oxygen is needed to form the nitrates
- 8Describe how denitrification worksSome bacteria convert nitrates back into nitrogen gas so that the oxygen can be used for respiration
- 9What kind of soil does denitrification take place in and why?Waterlogged, anaerobic soil as the bacteria must break down the nitrates due to low oxygen supply so it can be used in respiration
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- A level Biology (6.3.1 Ecosystems) Flashcards on 6.3.1 Nitrogen cycle, created by Sam Gunnell on 26/09/2019.
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- Sam Gunnell
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