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Membrane transport. In cellular biology, membrane transport refers to the collection of mechanisms that regulate the passage of solutes such as ions and small molecules through biological membranes, which are lipid bilayers that contain proteins embedded in them. The regulation of passage through the membrane is due to selective membrane ...
For human systems, see active mobility. 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 ...
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 ...
In contrast, paracellular transport is the transfer of substances across an epithelium by passing through an intercellular space between the cells. 1. It differs from transcellular transport, where the substances travel through the cell passing through both the apical membrane and basolateral membrane. 2. Renal physiology.
Intracellular transport is an overarching category of how cells obtain nutrients and signals. One very well understood form of intracellular transport is known as endocytosis. Endocytosis is defined as the uptake of material by the invagination of the plasma membrane. [4] More specifically, eukaryotic cells use endocytosis of the uptake of ...
Axonal transport. Axonal transport, also called axoplasmic transport or axoplasmic flow, is a cellular process responsible for movement of mitochondria, lipids, synaptic vesicles, proteins, and other organelles to and from a neuron 's cell body, through the cytoplasm of its axon called the axoplasm. [1] Since some axons are on the order of ...
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.
The endomembrane system is composed of the different membranes (endomembranes) that are suspended in the cytoplasm within a eukaryotic cell. These membranes divide the cell into functional and structural compartments, or organelles. In eukaryotes the organelles of the endomembrane system include: the nuclear membrane, the endoplasmic reticulum ...