how carbon is cycled through living organisms. Make clear connections to the process of Photosynthesis and Cellular Respiration

Question

Doing grade 9 biology and have a little bit of an issue fully understanding the carbon cycle. if you could help that would mean a lot!

Answer 1

Hi Calen

Let's start with a green plant. In the process of photosynthesis the plant utilizes energy from the sun to manufacture hydrocarbons (like glucose) from CO₂ and H₂O. A hydrocarbon stores the energy from the sun in the chemical bonds between its atoms. The hydrocarbons that the plant creates become part of its structure - its body- and a reservoir of energy.

You can think of cellular respiration as the inverse of photosynthesis. Photosynthesis stores energy by creating more the complicated hydrocarbon molecules. Cellular respiration breaks down the hydrocarbons into CO₂ and H₂O to release and use the energy that was holding the hydrocarbon together.

So, plants use CO₂ (carbon) to build molecules that store energy. Those molecules can later be broken down through cellular respiration in the plant to release the energy when the plant needs it. In addition, animals eat the plant. When the animal breaks down the plant's hydrocarbons through cellular respiration, the animal obtain the energy released, CO₂ is released into the atmosphere and some of the carbon in the molecules of the plant now become part of the animal.

Note that there are other paths for carbon. It stays in the bodies of plants and animals until they are broken down. But in terms of photosynthesis and cellular respiration, this is the basic story. Hope it helps!