Lecture 18 Nitrogen Cycle

Question 1

Prochlorococcus account for what huge percentage of photosynthetic oxygen production on the planet

Answer 1

20%

Question 2

What percentage of Nitrogen in the Atmosphere

Answer 2

78%

Question 3

Name the gases released to the atmosphere from nitrogen cycle

Answer 3

•Nitric oxide (NO)
•Nitrous oxide (N2O)
•Dinitrogen (N2)

Question 4

Name the 3 major processes of microorganism transformation in the nitrogen cycle

Answer 4

1.Nitrogen fixation

2.Denitrification

3.Nitrification

Question 5

Nitrogen Fixation reduction formula

Answer 5

8H+ +8 e-+ N2 = 2 NH3 + H2

Question 6

Example of a Heterocyst

Answer 6

Anabaena a Cyanobacteria

Question 7

Stages of Root Nodule formation:

Answer 7

1.Recognition
2.Excretion
3.Bacterial Invasion of root hair
4.Travel to main root
5.Formation of modified bacterial cells, bacteroids
6.Continued plant + bacterial division