Category: Respiration

Third stage of cellular respiration

Third stage of cellular respiration is the final common pathway of a cell to generate energy and occurs through the electron transport chain in which the metabolic intermediates of first and second stage of cellular respiration donate electrons to specific coenzymes – NAD (nicotinamide adenine dinucleotide) and FAD (flavin adenine dinucleotide) to produce energy rich [Continue]

Second stage of cellular respiration

Second stage of cellular respiration carried out through the Citric acid cycle/ Krebs cycle/ TCA cycle in which Acetyl Co-A is metabolized to carbon dioxide and water, and reduces co-enzymes that are re-oxidized through the electron transport chain, linked to the generation of ATP. It occurs totally in the mitochondria of a cell. The enzymes [Continue]

First stage of cellular respiration

Simple food molecules such as glucose, amino acid, and fatty acid can all be used as fuels for generation of energy in first stage of cellular respiration, but glucose is the principal fuel. Therefore, the principal process of first stage of cellular respiration is glycolysis. In glycolysis, enzymatic breakdown of glucose occurs in the cytoplasm [Continue]

What is cellular respiration?

Cellular respiration may be defined as a set of metabolic processes by which cells generate energy in the form of ATP (adenosine triphosphate) from the food molecules and release waste products. In cellular respiration, oxygen is required to generate large amount of energy but cells can also generate a small amount of energy without oxygen [Continue]

Oxidative Phosphorylation

Oxidative Phosphorylation – ATP Synthesis Oxidative phosphorylation occurs in mitochondria here transfer of electrons is coupled with ATP formation from ADP and Pi. It is driven by the strong thermodynamics tendency of O2 to become reduced, therefore, called oxidative phosphorylation. Oxidative phosphorylation accounts for only a small fraction of ATP generated in living cells of [Continue]

Electron Transport Chain

Respiratory Chain When NADH2 and FADH2 are produced in the Krebs cycle or in glycolysis are oxidized, ATP is produced. The electrons are transferred via several intermediate compounds before water is made. These electron carriers constitute electron transport system or respiratory chain. Components of Electron Transport System An electron system consists of: Cytochromes, four of [Continue]

krebs cycle

Krebs Cycle Hans A. Krebs first proposed a series of breakdown of pyruvate in the presence of oxygen, therefore the cycle is called Krebs Cycle. The cycle is also called citric acid cycle because formation of an important intermediate citric acid. krebs cycle takes place in the matrix of mitochondria. Entry of Pyruvate in to Mitochondria [Continue]

Mechanism Of Respiration

Mechanism Of Respiration Respiration suggests that respiration is multi-step process in which glucose is oxidized during a series of reactions. These reactions can be subdivided into three stages: Glycolysis It is carried out by a group of soluble enzymes located in the cytosol (liquid part of cytoplasm). Chemically, the glucose undergoes a limited amount of [Continue]

Glycolysis Cycle

Glycolysis Degradation of Glucose to Pyruvate Glycolysis definition:- In all living organisms, the initial phase of respiratory metabolism involves degradation of glucose in to pyruvate. The steps involved in the degradation were studied and explained by three biochemists namely Emden, Meyerhof and Parnas, therefore, it is also called EMP pathway. The enzymes for breakdown of [Continue]


The respiration which happens without oxygen is called anaerobic respiration. There are two perspectives about the source of fermentation: (an) It is a developmental sidestep. A few life forms use to hold glycolysis working under anaerobic conditions. (b) It is a biochemical remainder. It has developed right on time in the history of life. Around [Continue]