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2-3 Nitrogen Cycle.

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Presentation on theme: "2-3 Nitrogen Cycle."— Presentation transcript:

1 2-3 Nitrogen Cycle

2 Nitrogen Cycle Nitrogen – production of proteins and nucleic acids
79% of atmosphere – N2 gas Most plants and animals cannot capture nitrogen from the atmosphere Plants: Use nitrogen in the form of NO3- nitrates to produce amino acids then proteins Animals eat plant protein  digest it into amino acid use amino acids to build animal protein in the cells

3 Nitrogen Cycle Nitrogen Fixation Denitrification Nitrification


5 Nitrification Animals produce waste, die and decay
Nitrogen compounds introduced to soil Bacteria work on compounds breaking them into ammonium compounds then nitrates Nitrates are absorbed by plants

6 Nitrogen Fixation Nitrogen Fixation: process of converting atmospheric N2 into nitrates (NO3-) and ammonium ions (NH4+) Nitrogen-fixing bacteria: found on nodules of roots (legumes, alfalfa) Rhizobium convert N2 to nitrates to be used by plant plant gives bacteria sugars excess nitrates move into soil

7 Nitrogen Fixing Bacteria

8 Rhizobium

9 Nitrogen Fixation Lightning - N2 reacts with O2 - Nitrates are produced Nitrates fall to earth, enter soil, move into plants through the roots Crop rotation - balances input and output of N2

10 Denitrification Denitrifying bacteria: break down nitrates and nitrites into N2 gas gas reenters atmosphere Denitrifying bacteria carry out anaerobic respiration  found in tightly packed soil and or water logged soil Aeration slows down denitrification Allow oxygen entry to soil inhibits denitrifying bacterial growth Keeps grass green by keeping nitrates in the soil Nitrates are need for chlorophyll (protein) production



13 Nitrogen Cycle Diagram

14 Nitrogen Cycle Diagram
1 Atmospheric pool of nitrogen 2 Nitrogen-fixing bacteria in root nodules of legumes 3 Fertilizers 4 Soil nitrate 5 Nitrate take up by plant roots 6 Plant and animal proteins 7 Dead organisms 8 Decomposers 9 Nitrate bacteria Nitrate bacteria Denitrifying bacteria Lightning

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