Transfer of Energy

Alexander Ablozhey

Period 4 Science

Transfer of Energy through the Ecosystem

Photosynthesis and cellular respiration are connected through an important relationship. This relationship enables the existence of life. Notice that the equation for cellular respiration is the direct opposite of photosynthesis:

Cellular Respiration: C6H12O6 + 6O2 → 6CO2 + 6H2O

Photosynthesis: 6CO2 + 6H2O → C6H12O6+ 6O2

Photosynthesis results in the production of glucose from carbon dioxide and water using light energy within cellular organelles called “chloroplasts”, which exist in plants and algae. The important byproduct of this process is oxygen, which can, in turn, be used by other organisms within the ecosystem in the process of cellular respiration. During cellular respiration specialized organelles called “mitochondria” found in eukaryotic cells (cells that have a nucleus) can use oxygen and glucose to make ATP, resulting in the production of water and carbon dioxide to again be re-used by chloroplasts during photosynthesis. Water can thus be broken down to form oxygen during photosynthesis using light energy, while in cellular respiration oxygen can be combined with hydrogen to form water and ATP. While photosynthesis requires carbon dioxide, consumes light energy and releases oxygen, cellular respiration requires oxygen and releases carbon dioxide while producing ATP, which is also a type of energy. It is the released oxygen from plant photosynthesis that is used by animals (including us) for cellular respiration. Animals breathe in oxygen, which is carried by blood cells to the tissue cells. In tissue cells, oxygen allows cellular respiration to occur. Cellular respiration and photosynthesis are important parts of the carbon cycle. While cellular respiration produces carbon dioxide and releases it into the environment, photosynthesis reduces the amount of carbon dioxide in the atmosphere, helping keep carbon balance within the ecosystem. The transfer of energy occurs in chemical reactions during photosynthesis and cellular respiration, whereby light energy can be indirectly converted into the energy of phosphate bonds in the ATP to be used for a variety of cellular processes.