What is the purpose of cellular respiration?

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Cellular respiration is a process that occurs in cells to generate energy for the cell's life processes. The process occurs in the mitochondrion, the bean shaped organelle in the cell that takes glucose, a simple sugar, and oxidizes it with oxygen. The chemical reaction breaks apart the large glucose molecule, releasing free energy which takes the form of ATP, adenosine triphosphate. Carbon dioxide and water are released as waste products. Cellular respiration is the principle energy producer for all animal cells, and for plant cells at night, when the sun goes down and shuts down the other energy making process, photosynthesis. Sometimes, oxygen cannot be delivered fast enough to the cells. Then, the cells employ an alternate energy making process called fermentation. Fermentation produces energy production from the same glucose molecule without the use of oxygen. Between the two energy production methods, cellular respiration produces 38 ATP molecules to fermentation's 2 ATP molecules, causing it to be the more efficient energy production method.

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Cellular respiration is the process by which cells consume glucose and oxygen, and break it down into carbon dioxide and water. The process also generates ATP or adenosine triphosphate molecules. These are energy molecules and provide energy for various cellular operations (or functions). Chemically, the process can be written as:

`C_6H_12O_6 + 6O_2 -> 6 CO_2 + 6H_2O + ATP`

The main purpose of this process is to produce energy for maintaining life and other cellular functions. The carbon dioxide produced during the process helps in the greenhouse effect and keeps the planet warm enough for life.

Cellular respiration is complementary to the process of photosynthesis (by which green plants produce glucose molecules and oxygen). Photosynthesis is the process of food production and cellular respiration is the process of food breakdown. Both the processes are necessary for sustenance and propagation of life.  

Hope this helps. 

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