Nitrogen Cycle

Question 1

Why can’t most living organisms access nitrogen from the air?

Answer 1

It is inert and not very reactive.

Inert nitrogen gas (N2) cannot be directly utilized by most organisms.

Question 2

How do plants absorb nitrogen?

Answer 2

Plants can absorb nitrogen when it is bonded to oxygen to form nitogenous compounds, and is formed in the soil. These nitogenous compounds, called nitrates are dissolvable in water and plants absorb them through their roots

Question 3

What role do nitrogen-fixing bacteria play in the nitrogen cycle?

Answer 3

Converts nitrogen in the air into nitrates that the plant can absorb. These can be found in the root nodules of leguminous plants.

Question 4

How can oxides of nitrogen be formed in nature?

Answer 4

By lightning. They then dissolve in rain water to form nitric acid which ends up in the soil and combines minerals to form nitrates.

Question 5

What happens to nitrates when consumers feed on plants?

Answer 5

Consumers absorb the nitrates.

This allows the transfer of nitrogen through the food chain.

Question 6

What do decomposers release into the soil when breaking down organic matter?

Answer 6

Ammonium is released into the soil. Urea, faeces, and the decomposition of dead plants all contribute to the ammonification of the soil.

Question 7

What do nitrifying bacteria convert ammonium into?

Answer 7

Nitrites. It is then later transformed into nitrates. As a result, plants are able to recycle nitrates once more

Question 8

What do denitrifying bacteria do in the nitrogen cycle?

Answer 8

They absorb energy from nitrates and release nitrogen back into the air.

This process prevents the accumulation of nitrates in the soil.

Question 9

True or False: Plants can absorb nitrogen directly from the air.

Answer 9

False

Plants require nitrogen to be in a usable form, such as nitrates.

Question 10

What is nitrogen?

Answer 10

Nitrogen is a key element needed by living organisms to make proteins