Nitrogen Cycle and Processes

The nitrogen cycle is crucial for life, involving processes like nitrogen fixation, assimilation, ammonification, nitrification, and denitrification. Nitrogen is abundant in the atmosphere but must be converted into usable forms by plants and bacteria. These processes ensure a continuous exchange of nitrogen between the atmosphere and living organisms, supporting the synthesis of essential organic compounds.

What is the primary role of nitrogen in living organisms?

• It is an essential constituent of organic compounds like proteins and nucleic acids.

• It is a major component of carbohydrates.

• It is used for energy storage.

• It acts as a catalyst in metabolic reactions.

Which of the following processes is NOT part of the nitrogen cycle?

• Nitrification

• Denitrification

• Photosynthesis

• Nitrogen fixation

How do plants primarily obtain nitrogen?

• Directly from the atmosphere

• Through the absorption of ammonia, nitrites, and nitrates

• By consuming other plants

• Through photosynthesis

What natural phenomena contribute to nitrogen fixation?

• Ocean currents

• Volcanic eruptions

• Thunderstorms and lightning

• Earthquakes

Which bacteria are involved in biological nitrogen fixation?

• Streptococcus

• Lactobacillus

• Rhizobia

• E. coli

What is the process of converting nitrogenous waste into ammonia called?

• Assimilation

• Denitrification

• Ammonification

• Nitrification

During ammonification, what type of waste is decomposed?

• Carbohydrates

• Minerals

• Nitrogenous waste like urea and uric acid

• Lipids

What is the first step in the nitrification process?

• Conversion of nitrates to ammonia

• Oxidation of nitrites to nitrogen gas

• Oxidation of ammonia to nitrites

• Conversion of nitrites to nitrates

Which bacteria are responsible for denitrification?

• Cyanobacteria

• Rhizobia

• Thiobacillus

• Nitrosomonas

What is the end product of denitrification?

• Nitrates

• Molecular nitrogen

• Nitrites

• Ammonia