Nitrogen cycle

What is the nitrogen cycle?

The nitrogen cycle is the process by which nitrogen is converted between its various chemical forms in the environment.

Role of nitrogen-fixing bacteria?

These bacteria convert atmospheric nitrogen ($\displaystyle N_2$) into ammonia ($\displaystyle NH_3$), making nitrogen accessible to plants.

True or false: Nitrogen is essential for plant growth.

True, because nitrogen is a key component of amino acids and nucleic acids.

Difference between nitrification and denitrification.

Nitrification converts ammonia to nitrates, while denitrification converts nitrates back to nitrogen gas.

Fill in the blank: Ammonia is converted to ______ by nitrifying bacteria.

Nitrates.

What is ammonification?

The process where organic nitrogen from dead organisms is converted into ammonia by decomposers.

How does nitrogen return to the atmosphere?

Through denitrification, where nitrates are converted back to nitrogen gas by specific bacteria.

Question: What role do plants play in the nitrogen cycle?

Plants absorb nitrates and ammonium to synthesize proteins and nucleic acids.

What is a key outcome of the nitrogen cycle?

It maintains the balance of nitrogen in the atmosphere and soil, supporting life.

True or false: Nitrogen can be used directly by plants in its gaseous form.

False, because plants can only use nitrogen in the form of nitrates or ammonium.

What is the primary source of nitrogen in the atmosphere?

About 78% of the Earth's atmosphere is nitrogen gas ($\displaystyle N_2$).

Difference between organic and inorganic nitrogen.

Organic nitrogen is part of living organisms, while inorganic nitrogen includes compounds like ammonia and nitrates.

Role of decomposers in the nitrogen cycle?

Decomposers break down dead matter, releasing nitrogen back into the soil in forms plants can use.

What is eutrophication?

An over-enrichment of water bodies with nutrients, often due to nitrogen runoff, leading to algal blooms.

Explain the process of nitrogen fixation.

Nitrogen fixation is the conversion of nitrogen gas ($\displaystyle N_2$) into ammonia ($\displaystyle NH_3$) by bacteria.

What are nitrates?

Nitrates ($\displaystyle NO_3^-$) are soluble compounds that plants absorb for growth and development.

How do fertilizers impact the nitrogen cycle?

Fertilizers add excess nitrogen to the soil, which can lead to runoff and water pollution.

Fill in the blank: The process of converting nitrates to nitrogen gas is called ______.

Denitrification.