Nitrogen cycle

Question 1

Step 1 - Nitrogen fixation

Answer 1

Nitrogen fixing bacteria reduce nitrogen gas into ammonia

N2 + 6H –> 2NH3

Can happen artificially to produce fertilizer (Haber process)
And
Can also happen via lightening

Microorganisms involved are Nitrogen fixing bacteria that can be free living or mutualistic with legumes
(bacteria gains carbohydrates. legumes gain ammonia, which can be converted to amino acids)

Question 2

Step 2 - Nitrification

Answer 2

Some ammonia can be taken up by the roots. most is converted into nitrates through the following steps

1. one type of nitrifying bacteria oxidizes NH3 to NO2- (nitrite)
2. second type of nitrifying bacteria converts the nitrites to nitrate NO3-

Nitrates are taken up by the plant by active transport
microorganisms involved are aerobic nitrifying bacteria.

Question 3

Step 3 - Ammonification

Answer 3

Saprophytes break down protein in detritus to ammonia

Ammonia can be converted into amino acids. animals eat plants to gain nitrogen and it passes along the food chain (Assimilation)

Microorganisms involved are saprophytes

Question 4

Step 4 - Denitrification

Answer 4

Denitrifying bacteria convert nitrates in soil into nitrogen and nitrogen oxides

Microorganisms involved are anaerobic denitrifying bacteria

Question 5

Define Saprophyte

Answer 5

A plant, fungus or microorganism that lives on dead or decaying organic matter

Question 6

Define Detritus

Answer 6

organic waste

Question 7

Define Oxidation

Answer 7

Addition of oxygen, loss of electrons, loss of hydrogen and energy given out.

Question 8

Define Reduction

Answer 8

Loss of oxygen, gains of electrons, and gain of hydrogen

Question 9

Define Legumes

Answer 9

Type of plants (beans, peas that form a mutualistic relationship with nitrogen fixing bacteria)

Question 10

Define Assimilation

Answer 10

The absorption and digestion of food or nutrients by the body or any biological system

Question 11

Why is nitrogen important?

Answer 11

Nitrogen is essential for all living things because it is a major part of amino acids, which are the building blocks of proteins and of nucleic acids such as DNA. Needed for proteins and therefore needed for growth.

Question 12

78% of the earths atmosphere is nitrogen. Why do we need to recycle it?

Answer 12

Not in the usable form. Takes a lot of energy to convert to usable form (HABER process)