Nitrogen Cycle and Bacteria Concepts

The video explains the nitrogen cycle, highlighting nitrogen's presence in the atmosphere as N2 gas, making up 78% of it. The cycle involves converting atmospheric nitrogen into nitrates in the soil, which plants absorb to make proteins. This process is facilitated by natural methods like legumes and bacteria, as well as artificial methods using fertilizers. Decomposition and denitrification return nitrogen to the atmosphere. The video encourages viewers to explore related cycles like the carbon and water cycles.

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

• 50%

• 78%

• 92%

• 21%

Which type of plants have nodules in their roots that help fix nitrogen?

• Legumes

• Grasses

• Ferns

• Mosses

What role do bacteria in the soil play in the nitrogen cycle?

• They release nitrogen into the air

• They convert nitrogen into nitrates

• They absorb nitrogen from the air

• They prevent nitrogen fixation

How does lightning contribute to the nitrogen cycle?

• It releases nitrogen into the air

• It breaks down nitrates

• It fixes nitrogen into the soil

• It absorbs nitrogen from the soil

What is the role of fertilizers in the nitrogen cycle?

• They remove nitrogen from the soil

• They add nitrogen to the soil

• They convert nitrogen into gas

• They prevent nitrogen absorption

How do plants use the nitrates absorbed from the soil?

• To absorb sunlight

• To store energy

• To make proteins

• To produce oxygen

What happens to nitrogen when animals produce waste?

• It is converted into nitrates

• It is absorbed by plants

• It decays and adds nitrogen to the soil

• It is released into the air

Which bacteria are responsible for releasing nitrogen back into the atmosphere?

• Absorbing bacteria

• Fixing bacteria

• Denitrifying bacteria

• Nitrifying bacteria

What is the primary function of denitrifying bacteria in the nitrogen cycle?

• To convert nitrates into nitrogen gas

• To produce nitrates from nitrogen gas

• To absorb nitrogen from the air

• To fix nitrogen into the soil

What completes the nitrogen cycle by returning nitrogen to the atmosphere?

• Nitrifying bacteria

• Fertilizers

• Lightning

• Denitrifying bacteria