In the electron transport chain, which structure forms a channel in the inner membrane of the mitochondria and adds phosphate to ADP

ATP synthase

Explanation:

The ATP synthase complex is an enzyme located in the inner membrane of the mitochondrion that catalyzes the synthesis of ATP from ADP, a phosphate group and energy supplied by a proton (H+) flux. This ATP synthesis occurs during cellular respiration, which is a set of biochemical reactions by which certain organic compounds are completely degraded by oxidation to inorganic substances. This process provides usable energy to the cell in the form of ATP.

During cellular respiration, ATP synthesis is termed oxidative phosphorylation and the proton flux takes place between the intermembrane space and the mitochondrial matrix. ATP synthase produces ATP when protons flow through it. The proton flow creates a pH gradient and an electrochemical gradient. This proton gradient is used by ATP synthase to form ATP via oxidative phosphorylation. ATP synthase acts as an ion channel that "returns" protons to the mitochondrial matrix. During this return, the Gibbs free energy produced during the generation of the oxidized forms of electron transporters is released. This energy is utilized for ATP synthesis. It must then be considered that the electron transport chain and oxidative phosphorylation are coupled by the proton gradient.

b - the respond is innate and varies over time.

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i think the answer would be d