Nitrogen Cycle Review

What is nitrogen used for?

• RNA

• DNA

• Proteins

• Air

• Respiration

Why is nitrogen crucial for all life on Earth?

• It makes up 78% of the atmosphere.

• It is a primary component of water molecules.

• It is needed to make important biological molecules like DNA, RNA, and proteins.

• It helps in the decomposition of dead organisms.

Why is nitrogen gas (N2) from the atmosphere not directly usable by most living organisms?

• It is too heavy to be absorbed by plants.

• It forms a triple bond between its atoms, making it unreactive.

• It is only found in the upper atmosphere.

• It is toxic to most living things in its gaseous form.

What is the process by which nitrogen gas from the air is converted into a usable form like ammonia or ammonium in the soil?

• Nitrification

• Denitrification

• Nitrogen Fixation

• Ammonification

Which type of bacteria is responsible for converting ammonia into nitrites and then nitrates in the soil?

• Nitrogen-fixing bacteria

• Denitrifying bacteria

• Nitrifying bacteria

• Decomposing bacteria

What is the process that returns nitrogen gas (N2) from nitrates in the soil back into the atmosphere?

• Assimilation

• Ammonification

• Nitrification

• Denitrification