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Chemical Equation for Cellular Respiration

Chemical Equation for Cellular Respiration

The equation of cellular respiration provides information about the products and reactants of this most important biochemical process. Read to know how this process, the most crucial chemical reaction of life, works in every cell of the body.
Omkar Phatak
Every organism on Earth needs energy for survival. Its life is sustained through the process of respiration at the cellular level, which provides the requisite energy. This process makes every cell an independent unit that creates its own energy. This process of deriving energy is quite complex but it can be adequately summed up with the help of the chemical equation presented further.


Respiration, at the cellular level, is a set of connected metabolic processes that are directed towards converting stored biochemical energy in food, into ATP (Adenosine Triphosphate) molecules, which are the body's energy currency. Through subtle manipulation, with the help of enzymes, energy in the form of ATP molecules is derived from glucose. The production of glucose in turn, is done by plants, through the process of photosynthesis. Glucose and complex carbohydrates, created by plants, are consumed by other animals and processed to derive energy.

Food in the form of carbohydrates and fats is first broken down to simpler form of glucose molecules, which are then processed inside the cell to create ATP molecules.

Every action in the human body is made possible through use of the ATP molecules. That is why, they are called the energy currency of the body. Energy is derived through the conversion of ATP into ADP (Adenosine Diphosphate).

The Equation

Every metabolic process, including cellular respiration, is complex and constitutes a series of reactions that are connected with each other. It is made possible due to many enzymes and reactants at the cellular level that catalyze and control the flow of these reactions. The information for the execution of these reactions exists in the blueprints of the DNA molecule, present in every cell. Respiration is a complex cycle of reactions, made up of smaller cycles.

Aerobic means any process, that occurs in the presence of oxygen. Here's the chemical equation for plant, as well as animal respiration:

C6H12O6 + 6O2 --> 6CO2 + 6H2O + 36 or 38 ATP molecules

So the two primary raw materials of the process are glucose (C6H12O6) and oxygen. That's why, glucose levels in the blood need to be maintained or else, tiredness and cramping is experienced. The byproducts are carbon dioxide, water, and the energy currency in the form of ATP molecules. Let me provide a brief overview of what all happens in the respiratory process at a deeper level. There are three important steps:
  • Glycolysis: Glycolysis is the intermediate process which creates raw materials that include 3 pyruvate molecules, 2 NADH (Nicotinamide Adenine Dinucleotide) molecules, and a pair of ATP molecules as well. The products of glycolysis are further processed in the later phases.
  • Krebs Cycle: Krebs cycle is the premier process of respiration, which is also known as citric acid cycle. In this process, pyruvate molecules are processed, producing more ATP molecules.
  • Electron Transport Chain: This is the process which yields the maximum amount of ATP molecules.
This whole process creates 36 or 38 ATP molecules from a singular molecule of glucose. This is about 39% of the energy stored in the glucose molecule, which says a lot about the efficiency of this mechanism. Some ATP molecules are used up to power the respiration process itself.