Nitrogen Cycle Flashcard

Front

I am a gas that makes up most of the atmosphere, but most organisms can't use me directly. What am I?

Back

Nitrogen

Answer explanation

Nitrogen makes up about 78% of the Earth's atmosphere, but most organisms cannot use it directly. They rely on processes like nitrogen fixation to convert it into usable forms, unlike oxygen or carbon dioxide.

Front

I am a type of bacteria found in soil and root nodules of legumes, and I help convert atmospheric nitrogen into usable forms for plants. What am I?

Back

Nitrogen-fixing bacteria

Answer explanation

The correct answer is nitrogen-fixing bacteria, as they convert atmospheric nitrogen into forms usable by plants, primarily found in soil and root nodules of legumes. Denitrifying and nitrifying bacteria serve different roles.

Front

I am the process where atmospheric nitrogen is converted into usable nitrates for plants. What am I?

Back

Nitrification

Answer explanation

Nitrification is the process where atmospheric nitrogen is converted into nitrates, which plants can use. Denitrification removes nitrates, nitrogen fixation converts nitrogen to ammonia, and ammonification breaks down organic matter.

Front

I am a usable form of nitrogen that plants absorb from the soil to make DNA and proteins. What am I?

Back

Nitrates

Answer explanation

Nitrates are a usable form of nitrogen that plants absorb from the soil to synthesize DNA and proteins. Ammonia and nitrites are also forms of nitrogen, but nitrates are the primary source for plant uptake.

Front

I am the process where nitrates are broken down by bacteria, eventually releasing nitrogen gas back into the atmosphere. What am I?

Back

Denitrification

Answer explanation

The process described is denitrification, where bacteria convert nitrates into nitrogen gas, returning it to the atmosphere. This is distinct from nitrogen fixation, nitrification, and ammonification, which involve different nitrogen transformations.

Front

I am the chemical form of nitrogen (NH₃) produced from fish waste, plant debris, and other organic matter in aquatic environments. What am I?

Back

Ammonia

Answer explanation

The chemical form of nitrogen produced from fish waste and organic matter in aquatic environments is ammonia (NH₃). It is a key component in the nitrogen cycle, unlike nitrite, nitrate, or nitrogen gas.

Front

I am the process performed by decomposers that breaks down nitrogen-containing chemicals from dead organisms and waste into simpler forms like ammonia. What am I?

Back

Ammonification

Answer explanation

The process described is ammonification, where decomposers break down nitrogen-containing compounds from dead organisms and waste into simpler forms like ammonia, making it available for other organisms.

Front

I am the type of plant, like clover or soybeans, that often has a mutualistic relationship with nitrogen-fixing bacteria in its roots. What am I?

Back

Legume

Answer explanation

The correct answer is 'Legume' because plants like clover and soybeans belong to this category, which forms mutualistic relationships with nitrogen-fixing bacteria in their roots, enhancing soil fertility.

Front

I am a toxic form of nitrogen (NO₂) that can be converted from ammonia by aerobic bacteria. What am I?

Back

Nitrite

Answer explanation

The toxic form of nitrogen that can be converted from ammonia by aerobic bacteria is nitrite (NO₂). Nitrate is a further oxidation product, while ammonia and nitrogen gas are not toxic forms.

Front

I am a natural event where energy causes atmospheric nitrogen to react with oxygen, forming nitrates that dissolve in water and enter the soil. What am I?

Back

Lightning

Answer explanation

Lightning is a natural event that produces energy, causing atmospheric nitrogen to react with oxygen. This reaction forms nitrates, which dissolve in water and enrich the soil, making lightning the correct answer.