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  2. Transcellular transport - Wikipedia

    en.wikipedia.org/wiki/Transcellular_transport

    There are two types of active transport, primary active transport and secondary active transport. [citation needed] Primary active transport uses adenosine triphosphate (ATP) to move specific molecules and solutes against its concentration gradient. Examples of molecules that follow this process are potassium K +, sodium Na +, and calcium Ca 2+.

  3. Active and passive transformation - Wikipedia

    en.wikipedia.org/wiki/Active_and_passive...

    Geometric transformations can be distinguished into two types: active or alibi transformations which change the physical position of a set of points relative to a fixed frame of reference or coordinate system (alibi meaning "being somewhere else at the same time"); and passive or alias transformations which leave points fixed but change the ...

  4. Cell signaling - Wikipedia

    en.wikipedia.org/wiki/Cell_signaling

    Signaling molecules can be synthesized from various biosynthetic pathways and released through passive or active transports, or even from cell damage. Each cell is programmed to respond to specific extracellular signal molecules, and is the basis of development, tissue repair, immunity, and homeostasis.

  5. 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.

  6. Active transport - Wikipedia

    en.wikipedia.org/wiki/Active_transport

    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 ...

  7. Biology - Wikipedia

    en.wikipedia.org/wiki/Biology

    Biology is the scientific study of life. [1] [2] [3] It is a natural science with a broad scope but has several unifying themes that tie it together as a single, coherent field. [1] [2] [3] For instance, all organisms are composed of at least one cell that processes hereditary information encoded in genes, which

  8. Passive immunity - Wikipedia

    en.wikipedia.org/wiki/Passive_immunity

    In immunology, passive immunity is the transfer of active humoral immunity of ready-made antibodies.Passive immunity can occur naturally, when maternal antibodies are transferred to the fetus through the placenta, and it can also be induced artificially, when high levels of antibodies specific to a pathogen or toxin (obtained from humans, horses, or other animals) are transferred to non-immune ...

  9. Passive learning - Wikipedia

    en.wikipedia.org/wiki/Passive_learning

    The effectiveness of traditional instruction and passive learning methods have been under debate for some time. [2] The modern origins of progressive education, with active learning as a component, can be traced back to the 18th century works of John Locke and Jean-Jacques Rousseau, both of whom are known as forerunners of ideas that would be developed by 20th century theorists such as John Dewey.