Understanding the Nitrogen Cycle

What is nitrogen fixation?

• The breakdown of nitrogen compounds into nitrogen gas.

• The absorption of nitrogen by plant roots from the soil.

• The process of converting ammonia into atmospheric nitrogen.

• Nitrogen fixation is the conversion of atmospheric nitrogen into ammonia or related compounds.

True or False: Nitrogen fixation converts atmospheric nitrogen into ammonia.

• Nitrogen fixation is a process that releases nitrogen gas into the atmosphere.

• True

• Nitrogen fixation occurs only in plants.

• Nitrogen fixation converts ammonia into atmospheric nitrogen.

Which process involves the conversion of ammonia to nitrites?

• Nitrification

• Denitrification

• Ammonification

• Nitrogen fixation

True or False: Nitrification is a process that occurs in anaerobic conditions.

• Nitrification occurs in aerobic conditions.

• False

• Nitrification is a process that only happens in water.

• Nitrification is a type of fermentation.

What is the final step of nitrification?

• Conversion of ammonia to nitrite

• Conversion of nitrate to nitrogen gas

• Conversion of nitrite to nitrate

• Conversion of nitrite to ammonia

True or False: Denitrification returns nitrogen to the atmosphere as nitrogen gas.

• True

• Denitrification is a process that removes nitrogen from the atmosphere.

• Denitrification converts nitrogen gas into ammonia.

• Denitrification adds nitrogen to the soil.

What role do bacteria play in the nitrogen cycle?

• Bacteria are essential for nitrogen fixation, nitrification, and denitrification in the nitrogen cycle.

• Bacteria have no role in the nitrogen cycle.

• Bacteria decompose nitrogen into carbon dioxide.

• Bacteria are only involved in photosynthesis.

True or False: Ammonification is the process of converting organic nitrogen into ammonia.

• Ammonification is the process of converting ammonia into organic nitrogen.

• Ammonification occurs only in aquatic environments.

• Ammonification is the process of converting nitrogen gas into ammonia.

• True

Which bacteria are primarily responsible for nitrogen fixation?

• Staphylococcus aureus

• Escherichia coli

• Salmonella enterica

• Rhizobium, Azotobacter, Clostridium

True or False: Nitrifying bacteria are involved in the conversion of ammonia to nitrates.

• Nitrifying bacteria are only found in oceans.

• Nitrifying bacteria convert nitrates to ammonia.

• True

• Nitrifying bacteria are involved in photosynthesis.