Oxygen-Carbon Dioxide Cycle
- Water is one of the most important materials required by an organism.
Photosynthesis, green plants use energy from the sun to convert carbon dioxide and water into sugar and oxygen.
- Photosynthesis = Carbon dioxide + Water + Energy ->Sugar + Oxygen
Respiration is an energy-producing process in which a cell combines oxygen with sugars and gives off carbon dioxide and water.
- Respiration = Sugar + Oxygen -> Carbon Dioxide + Water + Energy
- Plants carry out both photosynthesis and respiration.
- All living things need nitrogen to make proteins.
- Although 80% of the air consists of nitrogen gas, few living things can use nitrogen in this form.
- Nitrogen gas must first be changed into one of a variety of nitrogen compounds and cycled through the environment.