BIOLOGY - Environment - Carbon Cycle part 1

Watch the first part of our Carbon Cycle videos, as part of environmental chemistry. Photosynthesis and respiration help carbon to be cycled in nature by using energy from the sun. As living things grow, they have to build up large polymer molecules from small molecules. Protein comes from joining amino acids together, cellulose and starch from joining sugars, and DNA from the bases, sugar and phosphate. Plants can make these simple molecules from the carbon they capture from photosynthesis with added elements from the minerals that they get from the soil. Animals have to get their molecules ‘ready made’ when they eat plants or other animals - but first they have to break the food polymers back into the small molecules through digestion. This all needs lots of energy. Living things get their energy from respiration. Some of the monomers (often carbohydrates in humans) have to be re-joined with oxygen. The carbon dioxide gets back into the food web through photosynthesis.