Nitrogen cycle

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Nitrogen can exist as...
A diatomic molecule, part of an organic molecule, part of an inorganic molecule
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What organic molecules contain nitrogen?
Proteins, Nucleotides, ATP
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The four stages for nitrogen to pass from one living organism to another:
Consumption, Digestion, Absorption, Assimilation
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Type of bacteria that breaks down dead plants/animals, faeces and urine:
Saprobiotic
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What is meant by the term Saprobiotic?
Extracellular digestion by releasing digestive enzymes onto the food source across their body surface.
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Another word for decay and decomposers...
Purefaction, putrefying bacteria
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What is meant by the term ammonification?
Proteins being broken down into ammonium ions by ammonifying bacteria
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First stage of nitrification:
Ammonium ions oxidised to form nitrites by nitrifying bacteria
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Example of nitrifying bacteria that oxidise ammonium ions...
Nitrosomonas
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Second stage of nitrification:
Nitrites oxidised to form nitrates by nitrifying bacteria to form nitrates
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Example of nitrifying bacteria that oxidise nitrites...
Nitrobacter
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Why do these bacteria do it?
Energy is released during the oxidation which is then used to fix carbon dioxide and then synthesise organic molecules
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What happens to the nitrates and any extra ammonium ions?
These ions are taken up by the roots of plants by active transport in the root hair cells
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What is the free living nitrogen fixing bacteria?
Azotobacter
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What is the nitrogen fixing bacteria forming a symbiotic relationship with legumes?
Rhizobium
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How does the Rhizobium benefit from the relationship?
Provided with: anaerobic conditions, carbohydrates from plants
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How does the legume benefit?
Provided with a supply of usable nitrogen containing compounds
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What is meant by the term denitrification?
Whan nitrate ions are reduced to form Nitrogen gas and oxygen for respiration
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An example of this kind of bacteria...
Pseudomonas
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Where do these bacteria live?
Anaerobic conditions such as flooded soil
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What is the result of the presence of these bacteria?
The area lacks available nitrogen sources (especially for plants)
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How can you improve this?
Ploughing and drainage of flooded soil
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How does this help?
Aerates the soil and encourages the growth of nitrifying bacteria
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Other cards in this set

Card 2

Front

Proteins, Nucleotides, ATP

Back

What organic molecules contain nitrogen?

Card 3

Front

Consumption, Digestion, Absorption, Assimilation

Back

Preview of the back of card 3

Card 4

Front

Saprobiotic

Back

Preview of the back of card 4

Card 5

Front

Extracellular digestion by releasing digestive enzymes onto the food source across their body surface.

Back

Preview of the back of card 5
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