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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 ...
Active mobility, soft mobility, active travel, active transport or active transportation is the transport of people or goods, through non-motorized means, based around human physical activity. [1] The best-known forms of active mobility are walking and cycling , though other modes include running , rowing , skateboarding , kick scooters and ...
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.
Human-powered transport is the transport of person (s) and/or goods (freight) using human muscle power. Unlike animal-powered transport, human-powered transport has existed since time immemorial in the form of walking, running and swimming, as well as small vehicles such as litters, rickshaws, wheelchairs and wheelbarrows.
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]
Enterocytes, or intestinal absorptive cells, are simple columnar epithelial cells which line the inner surface of the small and large intestines. A glycocalyx surface coat contains digestive enzymes. Microvilli on the apical surface increase its surface area. This facilitates transport of numerous small molecules into the enterocyte from the ...
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 ...
It includes other activities that involve movement; for example cleaning, working, active transport etc. Physical activity is defined as any voluntary bodily movement produced by skeletal muscles that requires energy expenditure. [1] Physical activity encompasses all activities, at any intensity, performed during any time of day or night. [2]