Bio1332 Biochemistry - Lecture Eighteen - Oxidative Phosphorylation

Electrons flow spontaneously along the chain, which means that they move without requiring any external force or energy input. This is a characteristic of electron flow in a circuit, where electrons move from a higher potential to a lower potential, creating an electric current. Therefore, the statement "True" accurately describes this phenomenon.

Oxidative phosphorylation occurs in the inner mitochondrial membrane. This is where the electron transport chain and ATP synthase are located, which are the key components of oxidative phosphorylation. The inner membrane is highly folded into structures called cristae, which increase the surface area available for these processes to occur. Therefore, the correct answer is the inner membrane, the inner mitochondrial membrane, and cristae.

The only route for the protons to get back into the matrix from the intermembrane compartment is through ATP synthase. ATP synthase is an enzyme located in the inner mitochondrial membrane that plays a crucial role in oxidative phosphorylation. It allows protons to flow back into the matrix, creating a proton gradient that drives the synthesis of ATP. This process is essential for the production of cellular energy in the form of ATP.

Each carrier in the chain has lower free energy than the preceding member. This means that as the carriers progress in the chain, their free energy decreases. This is consistent with the principle of energy conservation, as energy is often lost or converted into different forms as it moves through a system.

Rotenone, Amytal, Antimycin A, Cyanide, and Carbon monoxide are all inhibitors of oxidative phosphorylation. Oxidative phosphorylation is the process by which cells produce energy in the form of ATP. These inhibitors disrupt the electron transport chain, which is a key step in oxidative phosphorylation. Rotenone specifically inhibits complex I of the electron transport chain, while Amytal inhibits complex I and III. Antimycin A inhibits complex III, Cyanide inhibits complex IV, and Carbon monoxide inhibits complex IV as well. By inhibiting these complexes, the inhibitors prevent the production of ATP, leading to a decrease in cellular energy.

The 4th complex in the chain is Cytochrome c oxidase.

The second complex in the chain is named "Succinate Q-reductase" or "Succinate Q reductase". This complex plays a crucial role in the electron transport chain, specifically in the conversion of succinate to fumarate. It is responsible for transferring electrons from succinate to coenzyme Q (also known as ubiquinone), which then passes them on to the next complex in the chain. This complex is essential for the production of ATP through oxidative phosphorylation.

At the second complex, FADH2 is oxidized and loses two electrons to coenzyme Q via Fe-S clusters. This means that FADH2, which is a reduced form of flavin adenine dinucleotide, is converted back to its oxidized form, FAD, by donating two electrons to coenzyme Q. This electron transfer occurs through Fe-S clusters, which are iron-sulfur clusters present in the complex. Coenzyme Q acts as an electron carrier, accepting the electrons from FADH2 and transferring them to the next complex in the electron transport chain.

The correct answer is 24 electrons. In the stages of aerobic respiration before oxidative phosphorylation, the electron yield is 24. This includes the processes of glycolysis, the Krebs cycle, and the conversion of NADH and FADH2 to electron carriers. These stages generate a total of 24 electrons, which are then used in the final stage of oxidative phosphorylation to produce ATP.

Electron-motive force is converted into a proton motive force, which is then converted into phosphoryl transfer potential. The electron-motive force is generated during the electron transport chain in cellular respiration. This force is then used to pump protons across the membrane, creating a proton motive force. This proton motive force is a form of potential energy that can be harnessed to drive ATP synthesis through the process of chemiosmosis. The ATP synthesis involves the transfer of phosphoryl groups, which is facilitated by the proton motive force. Therefore, the correct answer is "Proton motive, Proton-motive."

The NADH-Q reductase consists of 34 polypeptide chains.

FALSE.
It is needed because ATP does not leave the catalytic site of the enzyme unless H+ flow through the pore.

The correct answer is the cytochrome bc1 complex.

Uncoupling proteins are capable of disrupting the tight coupling between electron transport and oxidative phosphorylation. They allow protons to flow back across the membrane without passing through ATP synthase, a process known as "proton leak." This uncoupling of electron transport from ATP synthesis can lead to a decrease in the production of ATP, as the energy from the electron transport chain is dissipated as heat instead of being used to generate ATP.

The flow of two electrons from NADH to QH2 leads to the pumping of four H+ ions from the matrix into the intermembrane compartment. The H+ ions cannot diffuse back into the matrix, generating a proton gradient.

The first complex in the electron transfer chain is called NADH-Q reductase or NADH Q reductase. This complex plays a crucial role in the electron transport chain by accepting electrons from NADH and transferring them to ubiquinone (Q). This transfer of electrons is an essential step in generating ATP through oxidative phosphorylation. Therefore, NADH-Q reductase is responsible for initiating the electron transfer chain and is a key component in cellular energy production.