Tag: bio-chemistry

Oxidative phosphorylation is a metabolic process, which is a part of respiration, which occurs in mitochondria. As a result of this process energy is released in the form of ATP.

Oxidative phosphorylation refers to synthesis of ATP by ADP and Pi driven by energy released from oxidation of reducing powers NADH and FADH2 by transfer of their electrons through electron trasnport chain to oxygen. Electron trasnport chain is present in inner mitochondrial membrane and passes the electrons down a series of carriers and pump protons into the intermembrane space. Oxygen serves as final electron acceptor in oxidation of NADH and FADH2 and the resulting proton gradient serves as energy source for the enzyme ATP synthase to synthesize ATP. So final products of oxidative phosphorylation are ATP, NAD and FAD. DPN (diphosphopyridine nucleotide), also called as NAD. Correct answers are D and B. NADP is coenzyme of photosynthetic light reactions. Puruvic acid is product of glycolysis. 

Oxidative phosphorylation is the metabolic pathway in which the mitochondria in cells use their structure, enzymes and energy released by the oxidation of nutrients to reform ATP in respiration.

Biological phosphorylation is of two types- protein phosphorylation and oxidative phosphorylation. In protein phosphorylation, the proteins get attached with a phosphate group. Oxidative phosphorylation is the metabolic pathway in which the mitochondria in cells use their structure, enzymes, and energy released by the oxidation of nutrients to reform ATP.

During one of the steps of Krebs cycle, succinic acid is converted to fumaric acid. The reaction is accompanied by coenzyme FAD (flavin adenine nucleotide). This oxidation reaction liberates less free energy as compared to other oxidation reactions. FAD$^+$ is the hydrogen acceptor in this reaction as there is very less free-energy change. In this reaction, succinic acid is oxidized to fumaric acid. At the same time, FAD$^+$ is reduced to FADH$ _2$. 

The electrons from NADH AND FADH$ _2$ flows through the inner mitochondrial membrane, thus forming a proton gradient i.e; building an H+ pump which flows through the membrane enzyme complex. An enzyme responsible for this process and energy generation is ATP synthase.

• Chemiosmotic phosphorylation is the process where ATP is formed by the ATP synthase complex which is present in the inner membrane of the mitochondria.
• The formation of ATP by this complex takes place when 2 hydronium ions are transported across the complex from the inter membrane space down its concentration gradient.
• Thus the formation of ATP in this process takes place due to the concentration gradient that is formed by the presence of hydronium ion that is formed by the ETS Chain when the electron along with hydronium ions are transported from the NADH and FADH.
• Therefore the answer 'the establishment of an electrochemical hydrogen ion (H+) gradient' is correct.
  

• Substrate level phosphorylation is the reaction where ATP is formed by the phosphate molecule that is taken from the substrate in the reaction.
• In glycolysis during the conversion of 1,3 bisphosphoglyceric acid to 3 phosphoglyceric acid and coversion of phosphophenol to pyruvic acid; one molecule of ATP is formed during each reaction.
• In kerb cycle during the formation of succinic acid from succinyl CoA GTP is formed which is a substrate level phosphorylation, afterwards this GTP is converted to ATP in a coupled reaction.
• No substrate level phosphorylation takes place in oxidative phosphorylation or ETS
• Therefore the answer 'glycolysis and the Krebs cycle' is correct.
  

• Glycolysis is the first part of the reaction that provides substrate for the further reaction of aerobic and anaerobic reaction. IT takes place in cytoplasm and does not require any oxygen.
• LActate respiration and fermentation both are the reaction that take place in the cells or the tissues which respiration in anaerobic conditions or when there is not enough oxygen.
• Oxidative phosphorylation is the process that takes place in the in the inner mitochondrial membrane where the electrons and hydronium ions are transported through a series of complexs and at the end the electrons and hydronium are accepted by the oxygen and water is formed, this is the process in the aerobic respiration where the oxygen is used and it cannot be completed with it.
• Therefore the answer option 'Oxidative phosphorylation' is correct.