Conversion of carbon to different forms (help)?

Question

I'm writing an essay on the carbon cycle, and my instructions mention that I must include a discussion about the conversion of carbon to different forms. I need some help with this please. Thank you.

Answer 1

Carbon exists in the nonliving environment as:

--carbon dioxide (CO2) in the atmosphere and dissolved in water     (forming HCO3−)

--carbonate rocks (limestone and coral = CaCO3)

--deposits of coal, petroleum, and natural gas derived from once-living things

--dead organic matter, e.g., humus in the soil

Carbon enters the biotic world through the action of autotrophs:

primarily photoautotrophs, like plants and algae, that use the energy of light to convert carbon dioxide to organic matter and to a small extent, chemoautotrophs — bacteria and archaea that do the same but use the energy derived from an oxidation of molecules in their substrate.

Carbon returns to the atmosphere and water by respiration (as CO2),

burning, and decay (producing CO2 if oxygen is present, methane (CH4) if it is not.

Answer 2

A couple of examples:

Combustion of any carbon-based fuel converts the carbon in the fuel into CO2, a gas.

Photosynthesis in plants takes CO2 from the atmosphere and converts it into carbon compounds which are then contained within the plant.

Other conversions include respiration (expels CO2 into the atmosphere), yeast reactions (the carbon in sugars is converted to CO2), and the dissolution of atmospheric CO2 into water.