Understanding Nitrogen and Phosphorus Cycles

What percentage of the atmosphere is made up of nitrogen gas?

• 10%

• 21%

• 5%

• 78%

Which enzyme is responsible for breaking the triple bond in nitrogen molecules?

• Nitrate reductase

• Lipase

• Nitrogenase

• Amylase

What type of bacteria converts ammonia into nitrates and nitrites?

• Ammonifying bacteria

• Nitrifying bacteria

• Denitrifying bacteria

• Nitrogen-fixing bacteria

What process returns nitrogen to the atmosphere in the nitrogen cycle?

• Ammonification

• Nitrification

• Denitrification

• Nitrogen fixation

Which element does not involve the atmosphere in its cycle?

• Phosphorus

• Nitrogen

• Carbon

• Oxygen

What is the role of lithotrophs in the phosphorus cycle?

• They break down rocks to release phosphorus.

• They fix nitrogen in the soil.

• They convert phosphorus into usable forms for plants.

• They decompose dead organic material.

What is the primary way phosphorus enters the biological cycles in aquatic systems?

• Photosynthesis by aquatic plants

• Through water erosion of rocks

• Decomposition of aquatic animals

• Direct absorption from the atmosphere

What is the main human activity that has increased the levels of nitrogen and phosphorus in ecosystems?

• Urbanization

• Deforestation

• Mining activities

• Use of synthetic fertilizers

Who was the scientist responsible for synthesizing ammonia from nitrogen?

• Marie Curie

• Albert Einstein

• Louis Pasteur

• Fritz Haber

What is the consequence of excessive use of nitrogen and phosphorus in agriculture?

• Enhanced water filtration

• Ecosystem disruption

• Increased crop yield

• Reduction in soil erosion