Cellular respiration is a common process that is carried out by many organisms to make and release energy. It is basically a process through which the cells covert glucose and oxygen to carbon dioxide and water, and hence release energy for ATP. ATP stands for adenosine triphosphate and is the free energy that is used by cells. It is basically an organic molecule that contains high-energy phosphate bonds. When a phosphate is passed from one ATP to another molecule, that molecule tends to gain energy. This reaction in which a molecule gains energy is known as endergonic reaction. The molecule from which the phosphate is removed tends to lose energy and give off heat. Such a reaction is known as exergonic reaction and the energy level of the molecule decreases.
Cellular respiration is different from photosynthesis and is usually an aerobic reaction, that occurs in the presence of oxygen. There are four distinct processes that divide the total cellular respiration process. Let us see the four steps involved in brief, before we move into the details of what is the cellular respiration equation.
- The first step involves glycolysis. Glycolysis takes place in the cell's cytoplasm and is an anaerobic process, that does not require oxygen. Glucose is broken down into two molecules of pyruvate in a 10-step process yielding 2 ATPs.
- The next step involves the entry of pyruvate into the mitochondria that leads to the production of two molecules of acetyl-coenzyme A and 2 molecules of CO2.
- The third step involves the Citric Acid Cycle (CAC). This is a 9-step reaction that takes place within the mitochondria. The reactions yield 2 ATPs and 4 CO2 molecules.
- The last step involves the Electron Transport System or cytochrome system that takes place with the help of enzymes that are located in the inner mitochondrial membrane. This step yields the maximum number of ATPs, that is 32 ATP molecules, which makes the total energy produced to 36 ATPs.
|C6H12O6 + 6O2 ➜ 6H2O + 6CO2 + 36 ATP|
Equation in Words
|Glucose + Oxygen ➜ Carbon dioxide + Water + Energy Released (ATP)|
Balanced EquationThe balanced cellular respiration equation yields 36 or 38 ATP molecules that depends on the extramitochondrial NADH-reducing equivalents, which are recycled for glycolysis like glycerol 3- phosphate that gives 36 ATP molecules and malate or aspartate shuttle yields 38 ATPs.
|C6H12O6 + 6O2 ➜ 6CO2 + 6H2O + 36 or 38 ATPs|
This is the balanced equation that yields energy. Cellular respiration helps cells break sugar which further helps in producing energy. It is an oxidation-reduction process or redox reaction. The oxidation of glucose as CO2 + H2O with an electron removed from C6H12O6. The reduction of oxygen to water with the passage of electron to oxygen is the reduction reaction. The NAD+ (nictotinadenine dinucleotide) is a co-enzyme that is reduced to NADH, when it picks up two electrons and one hydrogen ion, making it an energy carrier molecule. Flavin adenine dinucleotide (FAD+) gets reduced to FADH2, making it another co-enzyme that is an electron carrier.
The cellular respiration equation is a part of metabolic pathway that breaks down complex carbohydrates. It is an exergonic reaction where high-energy glucose molecules are broken down into carbon dioxide and water. It is also known as a catabolic reaction as a large molecule like a carbohydrate is broken down into smaller molecules.