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An electron transport chain (ETC [1]) is a series of protein complexes and other molecules which transfer electrons from electron donors to electron acceptors via redox reactions (both reduction and oxidation occurring simultaneously) and couples this electron transfer with the transfer of protons (H + ions) across a membrane.
The heterodimer consists of a light chain and a heavy chain covalently bonded by a disulfide bond. The light chain is the one that carries out transport, while the heavy chain is needed to stabilize the dimer. [6] There is some controversy over whether LAT1 is an uniporter or an antiporter. The transporter has uniporter characteristics of ...
Facilitated diffusion in cell membrane, showing ion channels and carrier proteins. Facilitated diffusion (also known as facilitated transport or passive-mediated transport) is the process of spontaneous passive transport (as opposed to active transport) of molecules or ions across a biological membrane via specific transmembrane integral proteins. [1]
As mentioned above, passive diffusion is a spontaneous phenomenon that increases the entropy of a system and decreases the free energy. [5] The transport process is influenced by the characteristics of the transport substance and the nature of the bilayer. The diffusion velocity of a pure phospholipid membrane will depend on: concentration ...
Diagram of the Na +-K +-ATPase. Since the ions are charged, they cannot pass through cellular membranes via simple diffusion. Two different mechanisms can transport the ions across the membrane: active or passive transport. [citation needed] An example of active transport of ions is the Na +-K +-ATPase (NKA).
The electron transport chain is responsible for establishing a pH and electrochemical gradient that facilitates the production of ATP through the pumping of protons. The gradient also provides control of the concentration of ions such as Ca 2+ driven by the mitochondrial membrane potential. [ 1 ]
In cell biology, diffusion is a main form of transport for necessary materials such as amino acids within cells. [1] Diffusion of solvents, such as water, through a semipermeable membrane is classified as osmosis. Metabolism and respiration rely in part upon diffusion in addition to bulk or active processes.
There are two types of active transport: primary active transport that uses adenosine triphosphate (ATP), and secondary active transport that uses an electrochemical gradient. This process is in contrast to passive transport , which allows molecules or ions to move down their concentration gradient, from an area of high concentration to an area ...