electrochemical gradient

(noun)

The difference in charge and chemical concentration across a membrane.

Related Terms

  • active transport
  • adenosine triphosphate

Examples of electrochemical gradient in the following topics:

  • Secondary Active Transport

    • In secondary active transport, a molecule is moved down its electrochemical gradient as another is moved up its concentration gradient.
    • Instead, another molecule is moved up its concentration gradient, which generates an electrochemical gradient.
    • The molecule of interest is then transported down the electrochemical gradient.
    • As sodium ion concentrations build outside the plasma membrane because of the action of the primary active transport process, an electrochemical gradient is created.
    • An electrochemical gradient, created by primary active transport, can move other substances against their concentration gradients, a process called co-transport or secondary active transport.
  • Electrochemical Gradient

    • The combined gradient of concentration and electrical charge that affects an ion is called its electrochemical gradient .
    • To move substances against a concentration or electrochemical gradient, the cell must use energy.
    • Active transport mechanisms, collectively called pumps, work against electrochemical gradients.
    • Electrochemical gradients arise from the combined effects of concentration gradients and electrical gradients.
    • Define an electrochemical gradient and describe how a cell moves substances against this gradient
  • Chemiosmosis and Oxidative Phosphorylation

    • Chemiosmosis is the movement of ions across a selectively permeable membrane, down their electrochemical gradient.
    • The uneven distribution of H+ ions across the membrane establishes both concentration and electrical gradients (thus, an electrochemical gradient) owing to the hydrogen ions' positive charge and their aggregation on one side of the membrane.
    • If the membrane were open to diffusion by the hydrogen ions, the ions would tend to spontaneously diffuse back across into the matrix, driven by their electrochemical gradient.
    • This protein acts as a tiny generator turned by the force of the hydrogen ions diffusing through it, down their electrochemical gradient.
    • ATP synthase is a complex, molecular machine that uses a proton (H+) gradient to form ATP from ADP and inorganic phosphate (Pi).
  • Proton Reduction

    • Anaerobic respiration utilizes highly reduced species - such as a proton gradient - to establish electrochemical membrane gradients.
    • An electrochemical gradient represents one of the many interchangeable forms of potential energy through which energy may be conserved.
    • An electrochemical gradient has two components.
    • Proton reduction is important for setting up electrochemical gradients for anaerobic respiration.
    • In contrast, fermentation does not utilize an electrochemical gradient.
  • Primary Active Transport

    • The sodium-potassium pump maintains the electrochemical gradient of living cells by moving sodium in and potassium out of the cell.
    • One of the most important pumps in animals cells is the sodium-potassium pump (Na+-K+ ATPase), which maintains the electrochemical gradient (and the correct concentrations of Na+ and K+) in living cells.
    • Primary active transport moves ions across a membrane, creating an electrochemical gradient (electrogenic transport).
    • Describe how a cell moves sodium and potassium out of and into the cell against its electrochemical gradient
  • Postsynaptic Potentials and Their Integration at the Synapse

    • Since the electrochemical gradient of sodium is steeper than that of potassium, a net depolarization occurs.
  • Energy Conservation and Autotrophy in Archaea

    • Instead, in archaea such as the Halobacteria, light-activated ion pumps generate ion gradients by pumping ions out of the cell across the plasma membrane.
    • The energy stored in these electrochemical gradients is then converted into ATP by ATP synthase.
  • F10 ATP Synthase

    • Energy is often released in the form of protium or H+, moving down an electrochemical gradient, such as from the lumen into the stroma of chloroplasts or from the inter-membrane space into the matrix in mitochondria.
  • Sodium Pumps as an Alternative to Proton Pumps

    • Usually, an H+ cycle includes generation of the transmembrane electrochemical gradient of H+ (proton motive force) by primary transport systems (H+ pumps) and its use for ATP synthesis, solute transport, motility and reverse electron transport.
    • While certain Na+-dependent functions, like Na+-dependent uptake of melibiose, proline, and glutamate, have been observed in many bacteria, the ion gradients that served as energy sources for these transports have been generated by primary H+ pumps and converted to Na+ gradients by Na+/H+ antiporters.
  • Equilibrium Constant and Cell Potential

    • If possible, a species will move from areas with higher electrochemical potential to areas with lower electrochemical potential.
    • In equilibrium, the electrochemical potential will be constant everywhere for each species.
    • It can also be used to determine the total voltage, or electromotive force, for a full electrochemical cell.
    • The Nernst equation gives a formula that relates the numerical values of the concentration gradient to the electrical gradient that balances it.
    • Empirically, an equilibrium situation would arise where the chemical concentration gradient could be balanced by an electrical gradient that opposes the movement of charge.
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