The Nitrogen, Oxygen and Carbon Cycles

What percent of the atmosphere is nitrogen gas?

78 percent.

Carbon is found in what three things, which are essential compounds found in all living things.

ALL carbohydrates, fats and proteins.

What do all organisms contain?

Carbon.

Where do fossil fuels come from?

Decaying organism under high pressure over hundreds of millions of years.

Carbon is also found deep underground in what?

Fossil fuels.

This also allows CO2 to be released where?

Into the atmosphere.

All living things need nitrogen to do what?

Make proteins.

What must nitrogen be transformed into to be used?

Nitrates (NO2, NO3).

Oxygen is also an important part of other whats, such as what and what?

Of other compounds, such as CO2 and H2O.

All things need what for cellular respiration to make energy to live and grow?

Oxygen.

What is oxygen a by-product of?

Photosynthesis in plants, phytoplankton and many species if bacteria.

How do plants interact with CO2 and O2?

Plants absorb CO2, make sugars and release O2 during photosynthesis.

Carbon is also found in the what from the decomposition of plant and animal remains and animal feces?

Soil.

What is nitrogen fixation (nitrification)?

When bacteria in the soil turn nitrogen gas into nitrates.

What is denitrification?

When other bacteria turn nitrates back into nitrogen gas and the cycle begins again.