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  2. Transcellular transport - Wikipedia

    en.wikipedia.org/wiki/Transcellular_transport

    Passive diffusion is the unassisted movement of molecules from high concentration to low concentration across a permeable membrane. [3] One example of passive diffusion is the gas exchange that occurs between the oxygen in the blood and the carbon dioxide present in the lungs. [4] Facilitated diffusion is the movement of polar molecules down ...

  3. Facilitated diffusion - Wikipedia

    en.wikipedia.org/wiki/Facilitated_diffusion

    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]

  4. Passive transport - Wikipedia

    en.wikipedia.org/wiki/Passive_transport

    Passive diffusion across a cell membrane.. Passive transport is a type of membrane transport that does not require energy to move substances across cell membranes. [1] [2] Instead of using cellular energy, like active transport, [3] passive transport relies on the second law of thermodynamics to drive the movement of substances across cell membranes.

  5. Membrane transport protein - Wikipedia

    en.wikipedia.org/wiki/Membrane_transport_protein

    Membrane transport protein. A membrane transport protein is a membrane protein involved in the movement of ions, small molecules, and macromolecules, such as another protein, across a biological membrane. Transport proteins are integral transmembrane proteins; that is they exist permanently within and span the membrane across which they ...

  6. Membrane transport - Wikipedia

    en.wikipedia.org/wiki/Membrane_transport

    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 ...

  7. Active transport - Wikipedia

    en.wikipedia.org/wiki/Active_transport

    In cellular biology, active is the movement of molecules or ions across a cell membrane from a region of lower concentration to a region of higher concentration —against the concentration gradient. Active transport requires cellular energy to achieve this movement. There are two types of active transport: primary active transport that uses ...

  8. Glucose uptake - Wikipedia

    en.wikipedia.org/wiki/Glucose_uptake

    Method of glucose uptake differs throughout tissues depending on two factors; the metabolic needs of the tissue and availability of glucose.The two ways in which glucose uptake can take place are facilitated diffusion (a passive process) and secondary active transport (an active process which on the ion-gradient which is established through the hydrolysis of ATP, known as primary active ...

  9. Diffusion - Wikipedia

    en.wikipedia.org/wiki/Diffusion

    Three-dimensional rendering of diffusion of purple dye in water. Diffusion is the net movement of anything (for example, atoms, ions, molecules, energy) generally from a region of higher concentration to a region of lower concentration. Diffusion is driven by a gradient in Gibbs free energy or chemical potential.