[22] Nitrogen Cycle

What is the nitrogen cycle?

the process by which nitrogen and its compounds are converted between different forms in the environment and living organisms.

What organisms carry out nitrogen fixation?

Nitrogen-fixing bacteria

What is nitrification?

Nitrification is the conversion of ammonia into nitrites and then nitrate

Which bacteria carry out nitrification?

nitrifying bacteria

What is assimilation in the nitrogen cycle?

Assimilation is when plants absorb nitrates from the soil and use them to make amino acids and proteins.

What is ammonification?

Ammonification is the process where decomposers break down dead organisms and waste, releasing ammonia back into the soil.

What is denitrification?

when denitrifying bacteria convert nitrates back into nitrogen gas, returning it to the atmosphere.

Why is denitrification harmful to soil fertility?

It removes nitrates from the soil, reducing the amount of nitrogen available for plant growth.

Name all the main processes in the nitrogen cycle.

Nitrogen fixation, nitrification, assimilation, ammonification, and denitrification.

What is the correct order of the main stages in the nitrogen cycle?

• Nitrogen fixation – nitrogen gas → ammonia/nitrates

• Nitrification – ammonia → nitrites → nitrates

• Assimilation – plants absorb nitrates to make proteins

• Ammonification – decomposers release ammonia from dead matter and waste

• Denitrification – bacteria convert unused nitrates in the soil to nitrogen gas

what is nitrogen fixation?

the process of turning nitrogen from the air into nitrogen compounds (such as nitrates) in the soil which plants can use

how does nitrogen fixation happen without nitrogen fixing bacteria

energy in a bolt of lightning makes nitrogen react with oxygen in the air to give nitrates