Nitrogen fixation

Question 1

What ability of an organism do we focus on in nitrogen fixation

Answer 1

The ability to form ammonia from Nitrogen gas

Question 2

Most abundant form of nitrogen? can it be used by organisms?

Answer 2

1. N2 Gas

2. cannot be utilized by most organisms

Question 3

Which form of nitrogen is most efficient for uptake of nitrogen?

Answer 3

1. Ammonia

2. Nitrate

Question 4

What form of nitrogen is easily passed from one organism to another through the food chain?

Answer 4

1. Amines
2. Nucleotides
3. Urea

Question 5

What is process of nitrogen fixation?

Answer 5

The process by which nitrogen gas (N2) is reduced to ammonia by the enzyme nitrogenase and then converted into cellular material

Question 6

What is the bulk of dinitrogen fixation?

Answer 6

The bulk is an enzyme driven process in prokaryotes referred to as diazotrophs (especially those that are symbiotic)

Question 7

greatest contribution to the nitrogen cycle?

Answer 7

from the symbiotic species

Question 8

Formula for nitrogen fixation? Is this process reduction or oxidation?

Answer 8

N2 + 8H+ + 6e- –> 2NH3 + H2 –> Cell synthesis
Dinitrogen Ammonia Proteins and nucleic acids
This entire process is nitrogen reduction

Question 9

What does nitrogenase do?

Answer 9

it catalyes three reduction reactions to reach the end result of the production of ammonia

Question 10

What does the nitrogenase reaction require ?

what type of process is it?

Answer 10

It requires 
1. 8 protons
2. hydrolysis of 16 atp molecules
It is an energy intensive process. 
intensive is requires a lot of work/effort

Question 11

Explain the process by which fixed nitrogen is transferred from the free-living prokaryotes to other organisms

Answer 11

The process is not clear but it is possible that fixed nitrogen can be available when the diazotrophs are eaten or when they die and decompose.

Question 12

Oxygen requirements of nitrogenase?

What conditions does it require?

Answer 12

1. its an oxygen sensitive enzyme

2. it requires anaerobic or extremely low oxygen conditions to be functional

Question 13

Out of anaerobic, facultative anaerobic, or obligate aerobic organisms, which one would have an easy time doing nitrogen fixation?

Answer 13

Anaerobic organisms because they cannot survive in presence of oxygen, which means they dont need any special strategy for permitting nitrogen fixation.

Question 14

Problem with facultative anaerobic and obligate aerobic organisms in nitrogen fixation?

Answer 14

they have to use oxygen for growth but also remove oxygen so that nitrogenase can function

Question 15

How does facultative anaerobic and obligate aerobic organisms deal with their problems of nitrogen fixation

Answer 15

1. Rapid respiration of available oxygen before onset (beginning of ) for nitrogenase function
2. Sequestering (separation) of the microbes in symbiotic bacteria
3. the use of protective compounds to reduce the amount of available oxygen

Question 16

What happens if synthetic nitrogen fertilizers are used improperly in excess?

Answer 16

They end up in run off from farms and pollute water bodies, where they can cause eutrophication and loss of oxygen

Question 17

Which organism carries out nitrogen fixation?

Answer 17

Only certain prokaryotes.

Question 18

Example of where to find nitrogen fixing organisms?

Answer 18

1. Freshwater ponds

2. Free living microorganisms ( anabaena, cyanobacterium)

Question 19

What two types of bacteria are capable of nitrogen fixation?

Answer 19

Free living

Symbiotic

Question 20

Once nitrogenase results in the production of ammonia, what does the ammonia further get converted to in free-living diazotrophs? What pathway does this?

Answer 20

it gets converted to glutamine through the glutamine synthetase pathway and thus incorporated into cellular material.