Carbon and The Carbon Cycle
Living organisms need carbon to:
- make food (green plants photosynthesise)
- make energy (through respiration)
- make new cells for growth and repair
Carbon cycles through ecosystems, moving repeatedly from one organism to another, and between organisms and the environment.
This video shows the Carbon Cycle and how this works
Living organisms need nitrogen to make proteins.
They cannot get it directly from the air because nitrogen gas is too stable to react inside an organism to make new compounds. Nitrogen must be changed into a more reactive form to allow plants and animals to use it.
Plants can take up and use nitrogen when it is in the form of nitrates or ammonium salts. Nitrogen fixation is the process when it is changed into a more reactive substance.
This video explains how the Nitrogen Cycle works