The Nitrogen Cycle Flashcards

Questions and Answers

Why is nitrogen important to organisms?

It carries out the many functions of life.

What percent of the atmosphere is nitrogen?

78%

What must happen to nitrogen before plants and animals can use it?

It must be fixed.

What organisms are able to 'fix' or convert nitrogen to be used by plants?

Special bacteria. Signup and view all the answers

Describe the nitrogen cycle.

Nitrous oxide from fossil fuels falls as nitric acid into rainwater; lightning creates soil nitrates; runoff from nitrates in farming enters water; bacteria in soil and water 'fix' nitrogen from the air; plants obtain nitrate ions from soil and water bacteria; animals eat plants; decomposer bacteria break down animal and plant matter into nitrogen compounds; nitrogen compounds eventually break down into gas and return to the air. Signup and view all the answers

How is carbon extracted from the atmosphere?

It is extracted from the atmosphere by plants through the process of photosynthesis. Signup and view all the answers

How do animals and humans get carbon?

Animals and humans get carbon by eating plants. Signup and view all the answers

What happens to the carbon in plants and animals when they die?

The carbon in the dead plants and animals gets trapped in the Earth. Signup and view all the answers

What are ways in which carbon is released into the atmosphere?

Carbon is released back into the atmosphere when rocks weather. Signup and view all the answers

What is a carbon sink?

Takes in more carbon than it gives off. Signup and view all the answers

Describe the carbon cycle.

Plants take in CO2 by photosynthesis; animals eat the plants; animals breathe out carbon dioxide after the plants give off oxygen; root and plant respiration; ocean uptake; decomposition of dead plants and animals; dead organisms + waste products = fossils and fossil fuels; carbon goes back into the atmosphere. Signup and view all the answers

Approximately what percentage of the atmosphere is made up of elements other than nitrogen and oxygen?

1% Signup and view all the answers

Why is nitrogen essential to the growth of a fungus, but not to the spread of rust?

A fungus is a living organism, while rust is not. Signup and view all the answers

What can you infer from the fact that nitrogen gas is useless to animals?

Animal cells can only use nitrogen when it's combined with other elements. Signup and view all the answers

What conclusion can you draw from the fact that sewage adds nitrogen compounds to the environment?

Animals get rid of nitrogen compounds in their waste. Signup and view all the answers

What do nitrification and denitrification have in common?

Both processes produce nitrogen gas. Signup and view all the answers

What is the main difference between denitrification and the other three steps of the nitrogen cycle?

Denitrification changes nitrogen into a gaseous form. Signup and view all the answers

Where can you find carbon?

Inside every living thing on Earth. Signup and view all the answers

How is the carbon cycle similar to the water cycle?

Both involve the transfer of substances between animals, plants, and the Earth. Signup and view all the answers

How do animals add carbon dioxide to the atmosphere?

Through breathing. Signup and view all the answers

What organisms in the ocean absorb the most carbon dioxide?

Algae and marine plants. Signup and view all the answers

What historical event led to a major imbalance in the carbon cycle?

Industrial Revolution. Signup and view all the answers

How does carbon become locked inside the earth?

The carbon-rich bodies of plants and animals decay into the earth after they die. Signup and view all the answers

How do carbon emissions lead to global warming?

By trapping the sun's heat in the atmosphere. Signup and view all the answers

Which of these is a factual statement about carbon?

Humans use far too much carbon-based fuel Signup and view all the answers

Study Notes

Nitrogen Importance

Nitrogen is essential for the functions of life in organisms.
It constitutes 78% of the Earth's atmosphere.

Nitrogen Cycle

Nitrogen must be fixed into ammonia before utilization by plants and animals.
Specific bacteria in the soil convert nitrogen into a usable form.
The nitrogen cycle includes:
- Nitrous oxide from fossil fuels transforming into nitric acid via rainfall.
- Soil nitrates formed by lightning.
- Runoff from farming introducing nitrates into water systems.
- Ingestion of plants by animals, followed by decomposition releasing nitrogen compounds back into the atmosphere.

Carbon Cycle

Plants extract carbon from the atmosphere through photosynthesis.
Animals and humans obtain carbon by consuming plants.
Upon death, carbon from organisms becomes trapped within the Earth.
Carbon is released into the atmosphere through rock weathering.
A carbon sink absorbs more carbon than it emits.
The carbon cycle involves:
- CO2 uptake by plants and its release by animals.
- Respiration processes in roots and plants.
- Oceanic carbon absorption.
- Decomposition resulting in fossil formation.

Atmospheric Composition

Elements other than nitrogen and oxygen account for roughly 1% of the atmosphere.

Nitrogen and Fungi

Nitrogen is crucial for fungi growth, distinguishing them as living organisms, while rust is a non-living entity.

Nitrogen Utilization by Animals

Animals cannot directly use nitrogen gas; it must be combined with other elements for cellular utilization.

Waste and Nitrogen Compounds

Sewage introduces nitrogen compounds into the environment through animal waste.

Nitrification vs. Denitrification

Both processes lead to the production of nitrogen gas, with denitrification uniquely converting nitrogen to its gaseous state.

Carbon Presence and Cycles

Carbon exists in every living organism on Earth.
Both the carbon and water cycles facilitate the transfer of substances among animals, plants, and the Earth.

Carbon Emissions

Animals contribute carbon dioxide to the atmosphere through respiration.
Algae and marine plants are key organisms that absorb significant amounts of carbon dioxide.
The Industrial Revolution historically disrupted the carbon cycle's balance, leading to increased emissions.
Carbon becomes locked in the Earth as the remains of carbon-rich organisms decay post-mortem.
Carbon emissions contribute to global warming by trapping solar heat in the atmosphere.

Carbon Facts

The statement that humans use excessive carbon-based fuels is factual.
Carbon ranks as the fourth-most abundant element in the universe.

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Description

Enhance your understanding of the nitrogen cycle with these flashcards. Learn about the significance of nitrogen in organisms, its atmospheric presence, and how it is fixed for plant use. Ideal for students studying ecology or environmental science.