Explain the mechanism of oxidative phosphorylation occurring in mitochondria.
Answers
The electron transport chain is a series of proteins and organic molecules found in the inner membrane of the mitochondria. Electrons are passed from one member of the transport chain to another in a series of redox reactions. Energy released in these reactions is captured as a proton gradient, which is then used to make ATP in a process called chemiosmosis. Together, the electron transport chain and chemiosmosis make up oxidative phosphorylation. The key steps of this process, shown in simplified form in the diagram above, include:
Delivery of electrons by NADH and FADH_2
2
start subscript, 2, end subscript. Reduced electron carriers (NADH and FADH_2
2
start subscript, 2, end subscript) from other steps of cellular respiration transfer their electrons to molecules near the beginning of the transport chain. In the process, they turn back into NAD^+
+
start superscript, plus, end superscript and FAD, which can be reused in other steps of cellular respiration.
Electron transfer and proton pumping. As electrons are passed down the chain, they move from a higher to a lower energy level, releasing energy. Some of the energy is used to pump H^+
+
start superscript, plus, end superscript ions, moving them out of the matrix and into the intermembrane space. This pumping establishes an electrochemical gradient.
Splitting of oxygen to form water. At the end of the electron transport chain, electrons are transferred to molecular oxygen, which splits in half and takes up H^+
+
start superscript, plus, end superscript to form water.
Gradient-driven synthesis of ATP. As H^+
+
start superscript, plus, end superscript ions flow down their gradient and back into the matrix, they pass through an enzyme called ATP synthase, which harnesses the flow of protons to synthesize ATP.
Answer:
When electrons are moved from NADH or FADH2 to oxygen by electron carriers, oxidative phosphorylation occurs, which is the process of creating ATP.
Explanation:
- The majority of the useable energy produced by the breakdown of fats or carbs is produced by the mitochondrial process known as oxidative phosphorylation.
- For instance, the citric acid cycle and glycolysis's breakdown of glucose result in the production of two molecules of FADH2, ten molecules of NADH, and four molecules of ATP.
- Following the transfer of electrons from NADH and FADH2 to molecular oxygen, an extra 32β34 ATP molecules are produced via oxidative phosphorylation.
- The important functions of protein complexes in the inner mitochondrial membrane, which eventually operate as the primary source of cellular energy, include electron transport and oxidative phosphorylation.