Oxidative Phosphorylation Lab Report

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Oxidative Phosphorylation & Electron Transport Chain The next reaction to be discussed is the Oxidative Phosphorylation and the respiratory electron transport chain also known as ETC. Oxidative phosphorylation is where ATP is created by the transfer of NADH or FADH2 to O2 by electron carriers. Oxidative Phosphorylation takes place in the inner membrane of the mitochondria. There is two processes in Oxidative Phosphorylation which are the electron respiratory chain and the production of ATP. In this pathway there is a series of enzyme complexes which occur on the inner membrane which oxidise NADH and pass the electrons to oxygen. Also the H+ ions are transported to the matrix to the intermembrane space.7 There is four steps in the Electron…show more content…
The cytochrome proteins contain a prosthetic heme group that carry electrons. This causes iron atoms to reduce and oxidise as it passes electrons. Complex III pumps proteins through membranes and electrons are passed to cytochrome c and is transported to Complex IV. Complex IV contains the cytochrome c, a, a3. Complex IV contains two heme groups and three copper ions. The cytochromes hold the O2 molecule between the iron and copper until the O2 is reduced. The reduced O2 collects two H ions from its surroundings and creates H2O. The removal of hydrogen ions create an ion gradient used in chemiosmosis.8 In chemiosmosis free energy from the reactions of the electron transport chain is used to pass hydrogen ions across the membrane. The passing of the H+ ions through the membranes creates an electrical gradient and concentration. This causes the H+ ions to collect on the outer surface of the membrane. The ions can’t diffuse through the membrane as it is nonpolar. Therefore they need an ion channel. This cannel is called ATP synthase. It is a membrane protein which allows H+ ions to pass from the matrix to the inner mitochondria membranes. ATP synthase works as a little generator, which can rotate due to the force of the H+ ions diffusing through it. The turning parts of ATP synthase helps in adding phosphate to ADP. Thus creating ATP, by harvesting potential energy that is stored in the ion gradient. This…show more content…
The rate at which O2 is consumed in the mitochondria is tightly regulated. It is limited by the availability of the substrate ADP. A way to determine the amount of energy in the mitochondria is the mass action ratio of ATP-ADP systems. High ratio means the ATP-ADP is nearly fully phosphorylated. The increase of energy in any energy requiring process leads to the increase breakdown of ATP to ADP and Pi which in turns lowers the mass action ratio. The increase of ADP available for oxidative phosphorylation leads to the increase of respiration. Leading to more ATP being generated. When mass-action ratio levels return to normal, respiration slows

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