Water Cycle and Nitrogen Cycle

What is this a picture of?

• Nitrogen cycle
• carbon cycle
• water cycle
• plant cycle

Which of the following describes the role of nitrogen-fixing bacteria in the nitrogen cycle? Nitrogen-fixing bacteria convert

• nitrates intro nitrogen gas
• ammonia into proteins
• nitrogen gas into ammonia
• proteins into nitrates

Organisms use nitrogen to form

• carbohydrates and lipids
• proteins and lipids
• lipids and nucleic acids
• proteins and nucleic acids

Nitrification is _________.

• production of nitrates from ammonia (NO3) for plants to use.

• conversion of nitrate to nitrogen gas, which is released back into the atmosphere.

• the condensing of water molecules.

This is the conversion of nitrate to nitrogen gas, which is released back into the atmosphere.

• Nitrogen Fixation

• Evaporation

• Denitrification

How nitrogen is "fixed" into useable form for plants

• only through action of bacteria
• only through lightning
• through action of bacteria & lightning
• through photosynthesis

According to this diagram, plants absorb

• nitrates

• nitrogen fixing bacteria

• animals

• decomposers

The conversion of Ammonia (NH3) to nitrite (NO2-) and then to nitrates (NO3-) is called

• ammonification

• Nitrification

• Denitrification

• Assimilation

Ammonification is the process of

• Formation of ammonia from nitrogen by nitrogen fixers

• Formation of ammonia from amino acids by decomposers

• Formation of ammonia from nitrates by nitrogen fixers

• Formation of ammonia from nitrates by decomposers and bacteria in the soil

What is the step labeled x in the figure ?

• ammonification

• denitrification

• nitrogen fixation

• nitrification