Nitrogen cycle

Question 1

in the nitrogen cycle microorganism are responsible for?

Answer 1

converting one form of nitrogen from another

Question 2

Who can fix nitrogen (N2) ?

Answer 2

Only certain prokaryotes

Question 3

Why only certain prokaryotes?

Answer 3

because N2 requires lot of energy to break the triple bond

Question 4

how do nitrogen fixers live ?

Answer 4

free-living(cyano) or symbiotic (Rhizobium)

Question 5

the nitrogen fixing the reaction is catalyzed by what ?

Answer 5

nitrogenase complex

Question 6

how many electrons are required to fix nitrogen ?

Answer 6

8 electron

Question 7

The electron come from what ?

Answer 7

pyruvate

Question 8

are the 8 electron completely used?

Answer 8

No, 2 are lost as H2 in the process

Question 9

Nitrogenase enzyme complex requires what to do so?

Answer 9

ATP,energy to break triple bond

Question 10

Ammonia is the final what and is used for ?

Answer 10

product and is used to produce amino acids

Question 11

Dinitrogenase reductase is inhibited by ?

Answer 11

the presence of oxygen

Question 12

quick quick overview?

Answer 12

flavodoxin reduced donne electron et dinitrogenase reduced gives electron

Question 13

name of Free-living nitrogen fixers?

Answer 13

• Azotobacter
• Beijerinckia
• Clostridium

Question 14

Free-living nitrogen fixers are widespread?

Answer 14

in soil

Question 15

free-living nitrogen fixers require?

Answer 15

a soil rich in organic matter to provide energy for nitrogen fixation

Question 16

Free-living Nitrogen fixers produce?

Answer 16

ammonia that can be used by plants (NH3, dissolves in water to produce ammonium NH3)

Question 17

Free-living nitrogen fixers that are strictly anaerobe?

Answer 17

Clostridium

Question 18

Azotobacter are what?

Answer 18

strict aerobe,enzyme is protected by a very high rate of O2 consumption,keeps the intrtacellular environment anaerobic

Question 19

all species of cyanobacteria are capable of N2 ?

Answer 19

no,

Question 20

Cyanobacteria are what?

Answer 20

major nitrogen-fixing organisms in nature

Question 21

Cyanobacteria produce energy by?

Answer 21

oxygenic photosynthesis, oxygen is produced in the cell.

Question 22

le fait que azotobacter leur interieur est anae robic ca fait que ?

Answer 22

oxygen peut pas inhibiter nitrogen fixation

Question 23

how can cyanobacteria fix nitrogen if they produce oxygen?

Answer 23

nitrogen fixation occurs in specialized anaerobic cells (heterocyts),which lack Photosystem 11 (does not produce O2)

Question 24

the heterocysts have a thick cell wall that slow down ?

Answer 24

the diffusion of O2

Question 25

The regular cells provide heterocytosts with?

Answer 25

carbohydrate (pyruvate )