What Role Do Mitochondria Play In Cellular Respiration – Cellular Respiration involves the oxidation and reduction of compounds. Oxidation and reduction are chemical processes that always occur together. They involve the transfer of electrons from one substance to another. Oxidation is the loss of electrons from a substance and reduction is the gain of electrons. Electron carriers are substances that can accept and give up electrons as needed. They turn on redox reactions in cells. The main electron transporter in respiration is NAD (nicotinamide adenine dinucleotide) (Oxford, 2014).

NAD initially has a positive charge and exists as NAD+. It accepts 2 electrons like this: two hydrogen atoms are removed from the substance being reduced. One of the hydrogen atoms is split into a proton and an electron. NAD+ accepts the electron and the proton (H+) is released. NAD accepts both the electron and the proton from the other H atom (Oxford, 2014).

What Role Do Mitochondria Play In Cellular Respiration

This reaction demonstrates that reduction can be achieved by accepting hydrogen atoms because they have one electron. Oxidation can be achieved through the loss of H atoms. Oxidation and reduction can also occur through the loss or gain of oxygen atoms. Phosphorylation of molecules makes them unstable. It is the addition of a phosphate ion to an organic molecule. For many reactions, the goal of phosphorylation is to increase the likelihood that the phosphorylated molecule will react. Another way of saying this is that phosphorylation can activate the molecule (Oxford, 2014).

Differences Between Chemiosmosis In Cellular Respiration And Photosynthesis

The hydrolysis (splitting) of ATP releases Energy to the environment and is therefore considered exothermic. Many reactions in the body are endothermic and therefore not spontaneous unless coupled with an exothermic reaction. Many metabolic processes are coupled to ATP hydrolysis (Oxford, 2014).

It is a semi-autonomous organelle, as it can grow and reproduce, but still depends on the cell for resources. 70S ribosomes and a bare DNA loop are found in the matrix.

There is an outer and inner membrane. The outer membrane separates the contents of the mitochondria from the rest of the cell; creating a specialized compartment for aerobic respiration.

The inner membrane is the site of oxidative phosphorylation. Contains ETCs and ATP synthase, which carry out the process. Cristae are tubular projections of the inner membrane that increase the surface area available for oxidative phosphorylation.

Cellular Respiration: What Is It, Its Purpose, And More

The space between membranes is where protons accumulate as a consequence of ETC. The accumulation is used to produce ATP via ATP synthase. The volume of the space is small, so a concentration gradient across the inner membrane increases rapidly.

The matrix is ​​the site of the Krebs Cycle and the binding reaction. The matrix fluid contains enzymes necessary to support reaction systems.

To summarize cellular respiration: Cells metabolize organic nutrients by slow oxidation. Enzymes break the covalent bonds that hold nutrients (like glucose) together. Energy is released in the form of ATP (adenosine triphosphate). Glycolysis is the first step. Occurs in the cytoplasm. A 6-carbon glucose is split into two 3-carbon molecules called pyruvate. Two ATP are needed for glycolysis to occur and the process produces 4 ATP. This is a net gain of two ATP at the end of glycolysis.

The two pyruvates enter the mitochondria and each lose carbon dioxide to become acetyl-CoA. The Krebs Cycle starts here. Two more carbon dioxide molecules are released during this process. More ATP is generated during the Krebs Cycle. The final step is the electron transport chain (ETC), which is a series of oxidation-reduction reactions. Most of the ATP comes from the ETC (34-38 molecules of one glucose molecule).

What Is The Role Of Mitochondria In Cellular Metabolism And Bioenergetics?

Glycolysis. This occurs in the absence of oxygen. It produces pyruvate and two ATP molecules. It converts a 6-C glucose into 2 3-C pyruvate molecules. This is not a one-step process; it is a metabolic pathway of many small steps. Phosphorylation reactions reduce the activation energy required for the reactions that follow and make them more likely to occur. Page 382 in your text shows the metabolic pathway of how glucose turns into fructose-1,6-bisphosphate. Fructose-1,6-bisphosphate is split to form two triose phosphate molecules. These molecules are then oxidized to form glycerate-3-phosphate in a reaction that produces enough energy to produce ATP. Oxidation is carried out by removing hydrogen atoms. Hydrogen is accepted by NAD+, which becomes NADH and H+. The phosphate group is transferred to ADP to produce more ATP and pyruvate. Page 383 shows the metabolic pathway for triose phosphate to become glycerate-3-phosphate.

Two pyruvate molecules are produced in glycolysis. If oxygen is present, it will be taken up by the mitochondria, where it will be fully oxidized.

This is not a one-step process. Carbon and oxygen are removed in the form of carbon dioxide in reactions called decarboxylations. The oxidation of pyruvate is achieved by the removal of pairs of H atoms. The H transporter NAD+ and a related compound called FAD accept the H atoms and pass them to the electron transport chain (ETC) where oxidative phosphorylation will occur. page 383, figure 2.

The link reaction. Here pyruvate is converted to acetyl coenzyme A (a-coe-A). Pyruvate is sent to the mitochondrial matrix. Once there, the pyruvate is decarboxylated and oxidized to form an acetyl group. Two high energy electrons are removed from pyruvate. These react with NAD+ to produce reduced NAD. This is called a linkage reaction because it links glycolysis to the Krebs Cycle and the Electron Transport Chain.

Regulation Of Cellular Respiration (article)

The Krebs Cycle. In this cycle, two more decarboxylations and four more oxidations occur. Most of the energy released in the oxidations of the binding reaction and the Krebs Cycle (KC) is used to reduce the H transporters NAD+ and FAD). The energy therefore remains in chemical form and can be passed on to the next part of respiration: oxidative phosphorylation. For each turn of the cycle, production of reduced NAD occurs three times, decarboxylation occurs twice, and reduction of FAD occurs once, and one molecule of ATP is generated (Oxford, 2014).

Oxidative phosphorylation. The energy released by oxidation reactions is transported to the mitochondrial cristae by the reduction of NAD and FAD. Reduced NAD is produced during glycolysis, the binding reaction, and KC. The final part of aerobic respiration is called oxidative phosphorylation (ox-phor) because ADP is phosphorylated to produce ATP using the energy released by oxidation. The oxidized substances include FADH2 generated in KC, and reduced NAD generated in glycolysis, the binding reaction, and KC. Thus, these molecules are used to transport the energy released in these steps to the crests (Oxford, 2014).

The electron transport chain. The transfer of electrons between carriers in the ETC is coupled to proton pumping. The final part of aerobic respiration is called oxidative phosphorylation because ADP is phosphorylated to produce ATP using the energy released by oxidation. The main oxidized substance is reduced NAD. Energy is released in a series of small steps carried out by a chain of electron transporters. As electrons pass from carrier to carrier, energy is used to transfer protons across the inner matrix membrane to the intermembrane space. Protons then flow through ATP synthase along its concentration gradient, providing the energy needed to produce ATP (Oxford, 2014). The whole point is for electrons to descend into the ETC to release energy. The resulting energy release helps move protons (H+) across the inner mitochondrial membrane. The energy of the moving electrons acts like a pump to push H+ into the intermembrane space.

. A chemical substance (H+) moves across a membrane along the concentration gradient. This releases the energy needed for ATP synthase to produce ATP. See p. 385 for the way. Oxygen is needed to bind free protons to form water and maintain the H gradient. Oxygen is the final electron acceptor in the mitochondrial ETC. The reduction of the oxygen molecule involves the acceptance of electrons and the formation of a covalent bond with H2. By consuming hydrogen, the protein gradient across the mitochondrial membrane is maintained so that chemiosmosis can continue (Oxford, 2014).Home Games and Quizzes History and Society Science and Technology Biographies Animals and Nature Geography and Travel Arts and Culture Money Videos

Mitochondrial Functions In Infection And Immunity: Trends In Cell Biology

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Cellular respiration, the process by which organisms combine oxygen with food molecules, diverting the chemical energy of these substances to life-sustaining activities and discarding, as waste, carbon dioxide and water. Organisms that do not depend on oxygen degrade food in a process called fermentation. (For longer treatments of various aspects of cellular respiration,

One goal of food degradation is to convert the energy contained in chemical bonds into the energy-rich compound adenosine triphosphate.

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