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Showing posts with the label movements across plasma membrane

Facilitated Diffusion

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What is facilitated diffusion? In membrane, there are protein channels (pores) that allow polar molecules (soluble in water but not soluble in lipids) to move through them. The molecules that move through these channels never come into contact with the hydrophobic layer or the membrane's polar surface because these channels provide a continuous pathway for molecules that are moving through them. In this type of diffusion, like simple diffusion, no energy is consumed. Large and polar molecules require help to pass through the membrane. This help is done by a type of protein called carrier (transport) protein . To pass through the membrane, a molecules binds (temporarily) with carries protein in lipid bilayer and is transported from an area of higher concentration to an area of lower concentration.  Related topics: Simple Diffusion
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Different movements across plasma membrane-Simple Diffusion-The Knowledge

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Movements across plasma membrane/How molecules move through plasma membrane? Membrane allows specific substances to cross through it (selective permeability).This feature prevent harmful substances to enter inside. There are different types of movements by which molecules enter or exit the cell. We will discuss on each type one by one. 1.Simple diffusion Spontaneous molecular motion triggers the molecules to move randomly from an area of higher concentration to an area of lower concentration. The molecules continue to move until they are equally distributed on both sides and they reach dynamic equilibrium. This type of movement of molecules is called simple diffusion. (L. diffundere , to spread).This type of movement occurs mostly for short-distance transport of substances moving in or out of the cell.  Related topics: Facilitated Diffusion
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