Where carbon is kept

The idea

Carbon, present in every protein, carbohydrate, fat and DNA molecule, circulates between the atmosphere (CO2), biosphere, geosphere (carbonate rocks, fossil fuels) and hydrosphere (dissolved CO2, marine shells).

Carbon everywhere

Proteins, carbohydrates, fats and DNA all contain carbon, the backbone of life.

Where else on the Earth might carbon be found?

• In air, living things, rocks and water
• Only in living things
• Only in the air

Four places

Open every tab.

A carbon map

Carbon keeps moving between these four places. Each is a place where carbon is kept for a while.

Carbon, present in every protein, carbohydrate, fat and DNA molecule, circulates between the atmosphere (CO₂), biosphere, geosphere (carbonate rocks, fossil fuels) and hydrosphere (dissolved CO₂, marine shells).

Notes

Carbon circulates between the atmosphere (CO₂), biosphere, geosphere (carbonate rocks, fossil fuels) and hydrosphere (dissolved CO₂, marine shells).

Check yourself

Which molecules contain carbon, the backbone of life?

Carbonate rocks and fossil fuels such as coal and oil store carbon in the …

In what form is carbon found in the atmosphere?

Dissolved CO₂ and marine shells hold carbon in the …

• Only DNA. Every protein, carbohydrate, fat and DNA molecule contains carbon.
• Proteins, carbohydrates, fats and DNA — correct. Yes!
• Only carbohydrates. Proteins, fats and DNA contain carbon too.
• Atmosphere. In the atmosphere carbon is in CO₂ gas.
• Hydrosphere. In the hydrosphere carbon is in dissolved CO₂ and marine shells.
• Geosphere — correct. Yes!
• CO₂ gas — correct. Yes!
• Coal. Coal is a fossil fuel in the geosphere.
• Marine shells. Marine shells are in the hydrosphere.
• Biosphere. In the biosphere carbon is in plants and animals.
• Hydrosphere — correct. Yes!
• Geosphere. In the geosphere carbon is in carbonate rocks and fossil fuels.