Cellular respiration is known to be one of the most majestic and elegant metabolic pathways found on the earth. It comprises of 3 stages:
•Glycolysis
•Krebs cycle Â
•ETC (Electron Transport Chain) Â
Throughout the cycle, ATP is generated in all the three phases of cellular respiration. However, the maximum ATP is generated in the ETC process. Â
Further Explanation:
Cellular respiration refers to the series of metabolic processes as well as reactions which occurs within the cells of the organisms. This process focuses on the conversion of the biochemical energy from the nutrients into the adenosine triphosphate and finally secrete out the waste products.
During this, a molecule of glucose is slowly broken down into the water and carbon dioxide. Some ATP or adenosine triphosphate is generated directly in the reactions which converts the glucose molecule. Oxidative phosphorylation is basically powered by the movement of the electron via the ETC which is a row of proteins pierced in the inner membrane of the mitochondria.
1.The process begins with the glycolysis. In this, the six-carbon sugar called glucose undergoes a row of chemical reactions and in the end, gets transformed into the two molecule of pyruvate which is a three-carbon molecule. During this, ATP is produced and NAD+ is converted into NADH. The process of glycolysis generates a net gain of two molecules of pyruvate, two molecules of ATP, and two NADH.
2.The second phase is the pyruvate oxidation wherein each molecule of pyruvate goes into the mitochondrial matrix and gets converted into the 2-carbon molecule and then binds with the coenzyme A which is called acetyl CoA. During this, NADH is generated while carbon dioxide is released. This stage generates two molecules of ATP for every molecule of glucose.
3.The third phase is the Krebs cycle or citric acid cycle wherein the acetyl CoA combines with the four-carbon molecule and undergoes a series of reactions, finally, generating four carbon starting molecule, NADH, ATP, and FADH2. The last phase is the ETC or ETC wherein NADH and FADH2 deposit their electrons and gets back into their previous forms like NAD+ and FAD.
The electrons move down the chain and release the energy which is used to pump out the protons of the matrix, thereby forming a gradient. The protons then move back into the matrix via the enzyme called ATP synthase which produces ATP. In the end, the oxygen accepts the electrons and then consumes the protons in order to form water. Finally, thirty eight molecules of ATP are formed, two glycolysis, two from Krebs cycle, and around thirty four from the ETC.
Learn more:
1. Learn more about photosynthesis link
2.Learn more about plants link
3.Learn more about respiration  link
Answer details:
Grade: High school
Subject: Biology
Chapter: Cellular respiration
Keywords:
Cellular respiration, glycolysis, Krebs cycle, ETC, citric acid cycle, adenosine triphosphate.
