N 2

1. N2 Lightning and the addition of fertlisers also adds nitrates to soil NO3- Nitrates are made into proteins in plants Animals get their protein by eating Which can be taken back up by plants and made into proteins Nitrogen fixing bacteria in soil and nodules of plants Death and decay Denitrifying bacteria use nitrates and release nitrogen into the air NO3- Bacteria break down the protein into nitrates

2. 80 % of the atmosphere is made up of nitrogen gas N2

3. nitrogen gas is very unreactive and very few organisms can extract it from the air

4. Nitrogen is essential for all organisms as it is needed to make proteins

5. Some terms you need to know first: • N2 Nitrogen • NH4+ Ammonium • NH3 Ammonia • NO2- Nitrite • NO3- Nitrate • NO2 Nitrogen oxide

7. Plants can easily make carbohydrates like sugars and starches

8. +

9. + NO3- nitrate ions need to be added to carbohydrates to make amino-acids

10. Amino acid + NO3- nitrate ions need to be added to carbohydrates to make amino-acids

11. Amino acid

12. Amino acid Amino acid

13. Amino acid Amino acid Amino acid

14. Amino acid Amino acid Amino acid Amino acid

15. Amino acid Amino acid Amino acid Amino acid Amino acid

16. Amino acid Amino acid Amino acid Amino acid Amino acid The amino-acids are joined together in chains to make polypeptides

17. But where does the nitrate come from?

18. But where does the nitrate come from?

19. But where does the nitrate come from? Certain bacteria are able to take atmospheric nitrogen and “fix” it into nitrate ions

20. N2

21. N2

22. N2

23. N2 NO3-

24. N2 NO3- These nitrogen fixing bacteria are either free living in the soil...

25. Or live in special nodules in the roots of plants These nitrogen fixing bacteria are either free living in the soil...

27. Or live in special nodules in the roots of plants These nitrogen fixing bacteria are either free living in the soil...

28. Or live in special nodules in the roots of plants These nitrogen fixing bacteria are either free living in the soil...

29. Or live in special nodules in the roots of plants These nitrogen fixing bacteria are either free living in the soil...

30. Or live in special nodules in the roots of plants These nitrogen fixing bacteria are either free living in the soil...

31. NO3-

32. NO3- The nitrate in the soil or in the root nodules can then be used by the plant to make proteins

33. Bacteria also help to recycle the nitrogen that has been made into protein

35. After death...

37. And of course the production of waste compounds containing nitrogen

39. Bacteria break down these proteins and waste products to release ammonia NH3

40. Bacteria break down these proteins and waste products to release ammonia NH3

41. protein Bacteria break down these proteins and waste products to release ammonia NH3

42. protein Bacteria break down these proteins and waste products to release ammonia NH3

43. protein Bacteria break down these proteins and waste products to release ammonia NH3

44. NH3 protein Bacteria break down these proteins and waste products to release ammonia NH3

45. NH3 The ammonia is further broken down by Nitrifying bacteria to release nitrates

46. NH3 NO3- The ammonia is further broken down by Nitrifying bacteria to release nitrates

47. Unfortunately some of the nitrates in the soil end up back as nitrogen in the atmosophere...

48. Nitrates

49. Nitrates

50. N2 Denitrifying bacteria use nitrates and release nitrogen into the air Nitrates