U2L7 Nitrogen Cycle Learning Check

What proportion of the atmosphere is made of nitrogen?

• 78%

• 21%

• 4%

• <1%

True or false: animals and plants cannot use nitrogen directly from the atmosphere.

• True

• False

Which processes convert nitrogen gas into nitrates?

• Nitrification

• Denitrification

• Nitrogen-fixation

• Lightning

Which of the following plants would contain nitrogen-fixing bacteria in their roots?

• Peas

• Tomatoes

• Aubergine/ eggplants

• Potatoes

What is the name given to the group of plants that can fix nitrogen into the soil?

How do nitrate compounds pass from plants to animals?

• Feeding

• Lightning

• Absorption

• Decomposition

Which of the following shows the correct sequence that nitrogen passes through to return to the soil from animal waste?

• Decomposition into ammonia -> nitrification into nitrites -> nitrification into nitrates

• Decomposition into ammonia -> nitrification into nitrates -> nitrification into nitrites

• Nitrification into nitrites -> nitrification into nitrates -> decomposition into ammonia

• Nitrification into nitrates -> nitrification into nitrites -> decomposition into ammonia

Which of these is not a type of bacteria in the nitrogen cycle?

• Nitrifying

• Nitrogen-fixing

• Denitrifying

• Nitrogen un-fixing

True or false: nitrifying bacteria and denitrifying bacteria have opposite functions in the nitrogen cycle.

• True

• False

Which process, not involving bacteria, adds nitrate compounds to the soil from the atmosphere?