nitrogen cycle

What plants help or are beneficial to the nitrogen cycle?

• pear trees

• peas

• dandelions

• clover

• peanuts

We need nitrogen to make

• proteins

• enzymes

• cells

• all of these

Round structures on the roots of certain plants

• lichens

• commensals

• cataracts

• nodules

What is the role of denitrifying bacteria

• change nitrate back into nitrogen gas

• change nitrogen gas into nitrate

• absorb carbon dioxide in the soil

• release oxygen gas into the atmosphere

This can transform nitrogen in the atmosphere into a usable form of nitrogen

• rain

• ice

• lightning

• sun

True or False. The nitrogen in the atmosphere is in the right form for living things to use.

• True

• False

What % of the air is made of nitrogen?

• 21%

• 52%

• 61%

• 78%

Which of these nitrogen cycle processes converts atmospheric nitrogen to a soil form of nitrogen that is usable by plants?

• nitrogen fixation

• nitrification

• denitrification

• ammonification

• assimilation

Which of these nitrogen molecules would be present in the atmosphere?

• NH₃

• NH₄⁺

• NO₃^-

• N₂

Which nitrogen cycle process is occurring when bacteria convert ammonium to nitrite and then into nitrate?

• nitrogen fixation

• nitrification

• denitrification

• ammonification

• assimilation