Carbon is an essential element for life on Earth. Every living organism has carbon compounds - such as fats and proteins - inside each of its cells. The carbon cycle shows how atoms of carbon can exist within different compounds at different times and be recycled between living organisms and the environment.
The carbon cycle is easiest to understand in terms of its processes and how carbon is converted. The three key processes and the conversions are shown in the table below.
|Process||Carbon starts as||Carbon ends as|
|Carbon dioxide||Glucose||Fuel (eg methane or wood)|
|Glucose||Carbon dioxide||Carbon dioxide|