Biochem 12.3 Oxidative Phosphorylation Overview

The energy stored in the proton gradient across the inner mitochondrial membrane, caused by a difference in both proton concentration and charge.

The process by which ATP is synthesized using the energy released from the flow of protons down their concentration gradient across the inner mitochondrial membrane.

The difference in proton (H+) concentration across the inner mitochondrial membrane, with the intermembrane space having a higher concentration than the mitochondrial matrix.

The difference in electrical charge across the inner mitochondrial membrane, with the intermembrane space being more positively charged than the mitochondrial matrix.

The enzyme responsible for synthesizing ATP using the energy released from the proton motive force.

The process of combining ADP with inorganic phosphate (Pi) to create ATP.

The transport of molecules across a membrane that requires energy, such as the movement of protons against their concentration gradient.

The transport of molecules across a membrane that does not require energy, such as the movement of protons down their concentration gradient.

ATP synthase catalyzes ATP synthesis by utilizing the proton gradient across the inner mitochondrial membrane.

ATP synthase couples the movement of protons down their electrochemical gradient with the synthesis of ATP.

ATP synthase is a transmembrane protein that facilitates the movement of protons across the inner mitochondrial membrane.

ATP synthase is a complex enzyme with two major domains, the F_o domain and the F₁ domain.

The F_o domain is a transmembrane complex that allows protons to flow through it. This domain contains subunits called the 'c subunits' that bind protons. As protons bind, the c subunits rotate, driving the F₁ domain to synthesize ATP.

The F₁ domain contains three sets of heterodimers, each consisting of an α subunit and a β subunit. These dimers surround the γ subunit, which is connected to the c subunits of F_o. As the c subunits rotate, the γ subunit rotates, causing conformational changes in the αβ complexes, which ultimately leads to ATP synthesis.

The F_o domain acts as a channel for protons to flow from the intermembrane space into the mitochondrial matrix, while the F₁ domain is responsible for ATP synthesis. The rotation of the c subunits within the F_o domain drives the rotation of the γ subunit within the F₁ domain, which in turn leads to conformational changes in the αβ dimers, resulting in ATP synthesis.

ATP synthase is a unique enzyme that couples the movement of protons down their electrochemical gradient with the synthesis of ATP. This process is known as chemiosmosis, and it is essential for energy production in cells.

The rotation of the y subunit in ATP synthase, driven by the proton gradient, causes conformational changes in aß complexes which facilitate ATP synthesis.

Three protons are required to drive one turn of the y subunit in ATP synthase, resulting in the production of three ATP molecules.

The transport of ATP from the mitochondrial matrix to the cytosol. ATP exits the matrix while ADP enters, facilitated by a transporter.

The movement of inorganic phosphate into the mitochondrial matrix, coupled with proton movement from the intermembrane space, ensures phosphate availability for ATP synthesis.

The process where ATP synthesis is directly linked to the proton gradient generated by the electron transport chain.

The disruption of the coupling between the electron transport chain and ATP synthase. This results in the energy stored in the proton gradient being dissipated without ATP production.

Substances that can disrupt the coupling between the electron transport chain and ATP synthase, leading to increased respiration without ATP production.

Molecules like 2,4-DNP or FCCP allow protons to cross the mitochondrial membrane without using ATP synthase. This disrupts the link between electron transport and ATP production.

The process where energy from the electron transport chain is used to generate heat instead of ATP. This occurs when protons leak across the membrane.

A protein channel in the inner mitochondrial membrane of brown fat cells, allowing protons to flow back into the matrix, generating heat instead of ATP.

A type of fat tissue that contains many mitochondria and is specialized for generating heat through uncoupled respiration.