Lecture 5_fillin version

Lecture 5_fillin version - iven by _. 5: The Nitrogen...

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ept assimilation involve ______________. Lecture 5: The Nitrogen and Phosphorus Cycles The nitrogen cycle (N) Like _________, nitrogen is needed by all organisms for proteins and nucleic acids (DNA, RNA) Though there is a lot of nitrogen gas in the atmosphere (78%), it doesn’t like to react with other elements. It is basically useless to life in gas form. Nitrogen gas: N 2 (g) (2 atoms of nitrogen) How is N 2 (g) changed to a usable form? What needs to happen? *Need to split N 2 and change it to a _______ _______ such as ammonia or nitrate before N can be used by plants and incorporated in tissue. (Nitrogen is abundant but immobile) Nitrogen cycle has 5 steps 1. Nitrogen fixation Nitrification 2. Assimilation 3. Ammonifacation 4. Denitrification 1. Nitrogen fixation : Conversion of atmospheric nitrogen into a form ________ to an organism is nitrogen fixation. First need to split N 2 ? How? Need enough _________. __________, volcanic action and combustion provide enough __________ . o Humans mimic the action of _________ by fixing nitrogen industrially with electric sparks YET 90% of nitrogen fixation is done by ____________. Example 1 Cyanobacteria use an __________ called nitrogenase to fix nitrogen (turn it to ammonia) in soil and water. ___________s lower the energy required to split N
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This note was uploaded on 10/07/2010 for the course NSC 2004C taught by Professor Farell during the Fall '09 term at Dowling.

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Lecture 5_fillin version - iven by _. 5: The Nitrogen...

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