Nitrogen Cycle

Select the term for the definition: when plants take in NH4 and convert it to usable N2

• ammonification
• nitrates (NO₃)
• atmospheric fixation
• assimilation

bacteria in oxygen-poor environments create nitrogen gas

• symbiotic
• denitrification
• atmospheric fixation
• assimilation

process where N2 in an organism’s body is changed to NH4 by decomposers

• ammonification
• atmospheric fixation
• denitrification
• nitrates (NO₃)

bacteria and fertilizers add this compound to the soil

• assimilation
• nitrates (NO₃)
• atmospheric fixation
• denitrification

process where N2 is broken apart by lightning, and nitrogen compounds fall with the rain

• atmospheric fixation
• symbiotic
• nitrates (NO₃)
• ammonification

type of relationship between plant roots and bacteria

• nitrates (NO₃)
• symbiotic
• atmospheric fixation
• assimilation

Which THREE characteristics accurately describe the element nitrogen?

• It makes up 78% of Earth’s atmosphere.
• Most organisms cannot use unreactive nitrogen gas.
• Nitrogen compounds are important parts of foods, fertilizers, and explosives.
• It is a yellow, reactive gas.
• There is no nitrogen in Earth’s atmosphere.

What is the largest reservoir that contains about 78% of all N2?

• bacteria
• atmosphere
• plants
• soil

Which is not a compound found in the nitrogen cycle?

• N2O
• NH4
• NO4
• NO3

Which is not a significant reservoir for nitrogen?

• rivers and streams
• plants
• bacteria
• atmosphere