All Flashcards
Why is nitrogen important for life?
It's a key component of proteins, DNA, and other vital biomolecules, essential for all living things.
What makes nitrogen a limiting nutrient?
It's essential for life but often in short supply, restricting growth and productivity.
What role do bacteria play in the nitrogen cycle?
Bacteria are involved in nitrogen fixation, nitrification, and denitrification; decomposers (some bacteria) perform mineralization.
Why is nitrogen fixation important?
It converts atmospheric nitrogen into forms usable by plants and other organisms.
Why is denitrification important?
It returns nitrogen to the atmosphere, completing the cycle and preventing excess nitrogen accumulation.
How do plants obtain nitrogen?
Plants absorb usable nitrogen (mostly nitrate) through their roots and assimilate it into their tissues.
What is the role of decomposers in the nitrogen cycle?
Decomposers break down dead organisms and waste, converting organic nitrogen back into inorganic ammonium.
What is the main reservoir of nitrogen?
The atmosphere, which is composed of approximately 78% nitrogen gas (N2).
What is the role of assimilation in the nitrogen cycle?
It's the process where plants incorporate nitrogen into their tissues, forming proteins and other biomolecules.
Why is the nitrogen cycle important for maintaining ecosystem health?
It ensures the continuous supply of nitrogen, a crucial element for plant growth and overall ecosystem productivity.
What are the steps of nitrogen fixation?
Atmospheric N2 is converted into ammonia (NH3) or nitrate (NO3) by biotic (bacteria) or abiotic (lightning, combustion) processes.
What are the steps of nitrification?
Ammonia (NH3) is converted into nitrite (NO2-), then nitrite is converted into nitrate (NO3-) by bacteria.
What are the steps of mineralization?
Decomposers break down dead organisms and waste, converting organic nitrogen back into inorganic ammonium (NH4+).
What are the steps of denitrification?
Nitrate (NO3-) is converted back into nitrogen gas (N2) and nitrous oxide (N2O) by specialized bacteria.
What is the assimilation process?
Plants absorb nitrate (NO3-) through their roots and incorporate it into their tissues to synthesize proteins and DNA.
Describe the overall flow of nitrogen in the nitrogen cycle.
Nitrogen moves from the atmosphere to the soil (fixation), then to plants and animals (assimilation), back to the soil (mineralization), and finally back to the atmosphere (denitrification).
How does nitrogen cycle through an ecosystem?
Nitrogen cycles through fixation, nitrification, assimilation, ammonification, and denitrification, with bacteria playing key roles in several steps.
Describe the role of bacteria in nitrification.
Bacteria convert ammonia (NH3) to nitrite (NO2-) and then to nitrate (NO3-), making nitrogen available to plants.
What happens to nitrogen after assimilation by plants?
Nitrogen becomes part of the plant's tissues, and consumers obtain nitrogen by eating the plants.
How does denitrification complete the nitrogen cycle?
Denitrification converts nitrate back into nitrogen gas, returning it to the atmosphere and balancing the cycle.
Define macronutrient.
An essential element required in large quantities for growth and survival.
Define limiting nutrient.
A nutrient that is in short supply and limits growth, even if other nutrients are abundant.
What is nitrogen fixation?
Conversion of atmospheric nitrogen (N2) into usable forms like ammonia (NH3) or nitrate (NO3).
Define nitrification.
Conversion of ammonia (NH3) into nitrite (NO2-) and then nitrate (NO3-).
What is assimilation?
The process by which plants absorb and incorporate usable nitrogen into their tissues.
Define mineralization (ammonification).
Decomposers convert organic nitrogen back into inorganic ammonium (NH4+).
What is denitrification?
Conversion of nitrate (NO3-) back into nitrogen gas (N2) and nitrous oxide (N2O).
Define eutrophication.
Excessive nutrient enrichment in a body of water, often leading to algal blooms and oxygen depletion.
What is biotic fixation?
Nitrogen fixation carried out by living organisms, such as bacteria.
What is abiotic fixation?
Nitrogen fixation carried out by non-biological processes, such as lightning or combustion.