Encyclopædia Britannica, Inc.

Cellular respiration is the process by which organisms employ oxygen to break down food molecules to get chemical free energy for cell functions. Cellular respiration takes place in the cells of animals, plants, and fungi, and as well in algae and other protists. It is frequently called aerobic respiration because the process requires oxygen (the root aer comes from the Greek word for "air"). In the absenteeism of oxygen, cells tin get energy by breaking down food through the process of fermentation, or anaerobic respiration. Of the 2 processes, cellular respiration is more than efficient, yielding considerably more energy than that released through fermentation.

Cellular respiration is a chemic reaction in which glucose is cleaved downwards in the presence of oxygen, releasing chemic energy and producing carbon dioxide and water as waste products:

glucose + oxygen → chemical energy + carbon dioxide + water

The energy released is captured in molecules of adenosine triphosphate, or ATP, which then supply information technology to fuel other cellular processes (meet biochemistry).

Encyclopædia Britannica, Inc.

All cells need free energy to function. Just as a car must fire fuel to get the energy it needs to run, the cell must burn fuel—for example, nutrient—to get energy to carry out the tasks of life. Glucose, a simple saccharide, provides the fuel the cell needs. Although energy is also stored in larger molecules, such equally complex carbohydrates and fats, they must be cleaved down into molecules of glucose earlier the cell can apply their free energy.

Most of cellular respiration takes place in sausage-shaped organelles called mitochondria. Although mitochondria play a fundamental function in other cellular processes, their main function is to produce large amounts of energy through cellular respiration. The number of mitochondria per prison cell varies; liver and muscle cells, which require large amounts of energy to part, may have thousands. (Run across too cell.)

Cellular respiration begins in the cell'southward cytoplasm. In that location, glucose is broken downward through a serial of chemical reactions to produce small molecules of a substance called pyruvate. This office of the process is chosen glycolysis; it does not crave oxygen and releases a modest amount of energy, which is captured by a few ATPs. The pyruvate molecules then enter the mitochondria, where they undergo a series of chemical reactions with oxygen. So much energy is released in these reactions that it takes many molecules of ATP to capture it all. The reactions likewise release hydrogen, which combines with oxygen to produce water; and carbon, which combines with oxygen to produce carbon dioxide. The water and carbon dioxide are released as waste products; the ATPs exit the mitochondria and deliver their captured energy to places in the cell where it is needed to power cellular activities.