Sunday, June 19, 2011

4.9 describe the stages in the carbon cycle, including respiration, photosynthesis, decomposition & combustion


"The element carbon is present in all living organisms. It's recycled through various processes, which are described in the carbon cycle."
Most chemicals in organisms contain carbon. When they die, the carbon is recycled, so future organisms can can use it.

The Steps: 

1. The movement of carbon between land, ocean, & atmosphere  is through the processes of photosynthesis and respiration. Carbon enters the atmosphere as carbon dioxide from respiration &
C6H12O6  + 6O2 arrow-right 6CO2 + 6 H2O + energy

Glucose+oxygen= carbon dioxide + water+ energy 

energy (sunlight) + 6CO2 + H2O arrow-right C6H12O6 + 6O2

Carbon dioxide + water (+ sunlight) --> glucose + oxygen 

2. Carbon dioxide is absorbed by producers to make carbohydrates (sugars) in photosynthesis.

3.  Animals feed on the plant passing the carbon compounds along the food chain. Most of the carbon they consume is exhaled as carbon dioxide formed during respiration. The animals & plants eventually then die.

4. The dead organisms are eaten by decomposers & the carbon in their bodies is returned to the atmosphere as carbon dioxide.

5. Sometimes decomposition is blocked. The plant and animal material may then be available as fossil fuel in the future for combustion. Fossil fuels ( oils+coals) ----> CO2


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