Nitrogen Cycle Questions

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  • 1/19 Questions

    Legumes host nitrogen fixing bacteria, and thus are good crops to plant to replenish the soil.

    • True
    • False
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About This Quiz

Explore the Nitrogen Cycle through targeted questions assessing knowledge on nitrogen fixation, the role of bacteria, and key processes like denitrification. Understand how nitrogen transitions between organic and inorganic forms, influencing ecosystems and biological functions.

Nitrogen Cycle Questions - Quiz

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  • 2. 

    Click all the living organisms that play an important role in changing nitrogen when it gets to the soil.

    • Bacteria

    • Reptiles

    • Whales

    • Plants

    Correct Answer
    A. Bacteria
    Explanation
    Bacteria play an important role in changing nitrogen when it gets to the soil. They are responsible for the process of nitrogen fixation, where they convert atmospheric nitrogen into a form that can be used by plants. This is a crucial step in the nitrogen cycle as it allows plants to obtain the necessary nitrogen for their growth and development. Reptiles, whales, and plants do not have the ability to change nitrogen in this way, making bacteria the correct answer.

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  • 3. 

    What process in the nitrogen cycle turns ammonium into nitrates?

    • Nitrogen fixation

    • Nitrification

    • Denitrification

    • Decayification

    Correct Answer
    A. Nitrification
    Explanation
    Nitrification is the correct answer because it is the process in the nitrogen cycle that converts ammonium into nitrates. This process involves two steps: the first step is the oxidation of ammonium to nitrite by nitrifying bacteria, and the second step is the oxidation of nitrite to nitrate by different nitrifying bacteria. Nitrates are an important form of nitrogen that plants can easily absorb and use for growth, making nitrification a crucial step in the nitrogen cycle.

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  • 4. 

    What is the most common way that nitrogen fixation occurs?

    • Lighting

    • Nitrogen-fixing bacteria

    • Fossil fuel combustion

    • Forest fires

    Correct Answer
    A. Nitrogen-fixing bacteria
    Explanation
    Microorganisms, particularly bacteria, play major roles in all of the principal nitrogen transformations. Nitrogen-fixing bacteria often form symbiotic relationships with host plants. In fact, most nitrogen-fixing is carried out by bacteria.

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  • 5. 

    Atmospheric nitrogen (N2 gas) is easily taken up and used by plants and animals.

    • True

    • False

    Correct Answer
    A. False
    Explanation
    Although the majority of the air we breathe is N2, most of the nitrogen in the atmosphere is unavailable for use by organisms. In order for plants and animals to be able to use nitrogen, N2 gas must first be converted to a different form, such as ammonium (NH4+), nitrate (NO3-), or organic nitrogen.

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  • 6. 

    How do plants obtain nitrogen? 

    • Plants do not use nitrogen 

    • From water 

    • From the soil using their roots 

    • From the atmosphere 

    Correct Answer
    A. From the soil using their roots 
    Explanation
    The nitrogen in plants comes from the soil. Bacteria in the soil take nitrogenous wastes and convert it into forms of nitrogen that plants can use. Plants then take up nitrogen through their roots.

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  • 7. 

    What is the largest natural reservoir nitrogen on earth?

    • Atomosphere

    • Sun

    • Ocean

    • Dirt

    Correct Answer
    A. Atomosphere
    Explanation
    The atmosphere is the largest natural reservoir of nitrogen on Earth. Nitrogen makes up about 78% of the Earth's atmosphere and is crucial for many biological processes. It is an essential element for the formation of proteins and DNA in living organisms. Nitrogen is constantly cycled through the atmosphere, land, and water through various processes like nitrogen fixation, nitrification, and denitrification. The other options, such as the sun, ocean, and dirt, do not contain as much nitrogen as the atmosphere.

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  • 8. 

    What is the chemical formula for the nitrogen gas that is in the atmosphere?

    Correct Answer
    N2
    Explanation
    The chemical formula for nitrogen gas in the atmosphere is N2. This means that nitrogen gas consists of two nitrogen atoms bonded together. This formula is commonly used to represent the nitrogen gas that makes up about 78% of Earth's atmosphere.

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  • 9. 

    Why can plants not utilize naturally occurring nitrogen gas?

    • Plants cannot break the triple bond between the two nitrogen atoms

    • Lack of nitrogen-fixing bacteria

    • There are insufficient amounts available in the atmosphere

    • Most of the nitrogen is stored as nitrate (NO3-)

    Correct Answer
    A. Plants cannot break the triple bond between the two nitrogen atoms
    Explanation
    Plants cannot utilize naturally occurring nitrogen gas because they are unable to break the triple bond between the two nitrogen atoms. Nitrogen gas is composed of two nitrogen atoms tightly bonded together, and plants do not possess the enzymes necessary to break this strong bond. Instead, they rely on nitrogen-fixing bacteria to convert nitrogen gas into a usable form, such as nitrate (NO3-), which can be taken up by plants and used for growth and development.

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  • 10. 

    Which process in the nitrogen cycle turns dead plants and animals to ammonium?

    • Nitrogen fixation

    • Nitrification

    • Ammonification

    • Deacidification

    Correct Answer
    A. Ammonification
    Explanation
    Ammonification is the process in the nitrogen cycle that converts dead plants and animals into ammonium. This occurs through the decomposition of organic matter by bacteria and fungi. During ammonification, these decomposers break down the proteins and other nitrogen-containing compounds present in dead organisms, releasing ammonium as a byproduct. This ammonium can then be further transformed into other nitrogen compounds through processes like nitrification and denitrification.

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  • 11. 

    What percent of the air around you is made of nitrogen gas, N2?

    Correct Answer
    78, 78%
    Explanation
    Approximately 78% of the air around us is made up of nitrogen gas, N2. Nitrogen is the most abundant gas in the Earth's atmosphere and is essential for many biological processes. This high percentage of nitrogen in the air is crucial for the survival of living organisms and plays a significant role in maintaining the balance of gases in the atmosphere.

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  • 12. 

    Which process releases dinitrogen gas (N2) back into the atmosphere?

    Correct Answer
    denitrification
    Explanation
    Correct! In the process of denitrification, bacteria convert nitrate to dinitrogen (N2), a gas that is rapidly lost to the atmosphere.

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  • 13. 

    In the nitrogen cycle, which process involves the conversion of atmospheric nitrogen gas (N2) into ammonia (NH3) or ammonium (NH4+) that can be used by plants?

    Correct Answer
    Nitrogen fixation, Fixation
    Explanation
    Nitrogen fixation is the process in the nitrogen cycle where atmospheric nitrogen gas (N2) is converted into ammonia (NH3) or ammonium (NH4+). This conversion is carried out by nitrogen-fixing bacteria, which make nitrogen from the air available in a form that plants can use to synthesize proteins and other essential compounds. Denitrification (A) is the process where nitrates are converted back into atmospheric nitrogen gas, nitrification (B) is the conversion of ammonia into nitrite and nitrate, and nitrate assimilation (D) is the incorporation of nitrate into plant tissues.

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  • 14. 

    What process turns nitrogen into ammonium?

    • Nitrogen fixation

    • Ammonification

    • Denitrification

    • Yea

    Correct Answer
    A. Nitrogen fixation
    Explanation
    Nitrogen fixation is the process that converts nitrogen gas (N2) into ammonium (NH4+), which is a form of nitrogen that can be utilized by plants and other organisms. This process is carried out by certain bacteria and archaea, either in the soil or in the root nodules of leguminous plants. These microorganisms have the ability to convert atmospheric nitrogen into a form that can be incorporated into organic compounds. Ammonification, on the other hand, is the process by which organic nitrogen compounds are converted into ammonium, while denitrification is the process that converts nitrate (NO3-) back into nitrogen gas.

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  • 15. 

    Organic nitrogen is converted back to inorganic nitrogen like ammonium through the process:

    • Nitrogen fixation

    • Decay

    • Answer not here

    • Birth

    Correct Answer
    A. Nitrogen fixation
    Explanation
    After nitrogen is incorporated into organic matter, it is often converted back into inorganic nitrogen by decay. When organisms die, bacteria and fungi consume organic matter. During decomposition, a significant amount of the nitrogen contained within the dead organism is converted to ammonium.

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  • 16. 

    Ammonium (NH4) stays in the soil, while nitrate (NO3) is easily leached out. Why do they behave so differently?

    • NO3 is broken down by bacteria, so it is easily carried away

    • NH4has a positive charge and sticks to soil particles

    • NH4 is unavailable to organisms, so it remains unchanged in the soil.

    • NO3 is only produced when water is flowing through soil.

    Correct Answer
    A. NO3 is broken down by bacteria, so it is easily carried away
    Explanation
    Correct! In nitrification, some positively charged ammonium ions are converted to negatively charged nitrate. The positive charge prevents ammonium nitrogen from being leached out of the soil by rainfall. In contrast, the negatively charged nitrate ion is not held by soil particles and so can be washed out of the soil and into surface and groundwater.

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  • 17. 

    Why is nitrogen important to live on Earth?

    • It is used to make DNA

    • It is used to make chlorophyll in plants

    • It is used to make proteins

    • It is used to make amino acids

    • It creates mud

    Correct Answer(s)
    A. It is used to make DNA
    A. It is used to make chlorophyll in plants
    A. It is used to make proteins
    A. It is used to make amino acids
    Explanation
    Nitrogen is important for life on Earth because it is used to make DNA, chlorophyll in plants, proteins, and amino acids. DNA is the genetic material that carries the instructions for the development and functioning of all living organisms. Chlorophyll is the pigment that allows plants to photosynthesize and convert sunlight into energy. Proteins are essential for the structure, function, and regulation of cells, tissues, and organs. Amino acids are the building blocks of proteins. Therefore, nitrogen plays a crucial role in the fundamental processes of life and is necessary for the existence and functioning of living organisms.

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  • 18. 

    Once bacteria have fixed nitrogen, it can be taken up by plants and animals, where it is used in the production of

    Correct Answer(s)
    proteins
    Explanation
    Correct! Nitrogen (N) is an essential component of DNA, RNA, and proteins. In the process of nitrogen fixation, bacteria convert N2 from the atmosphere into ammonium, a form that plants and animals can use. The ammonia produced by nitrogen fixing bacteria is used to make protein.

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  • Jun 25, 2024
    Quiz Edited by
    ProProfs Editorial Team
  • Feb 09, 2020
    Quiz Created by
    Kyle Pearson
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