martes, 26 de abril de 2011

Cell Menbrane



Fluid Mosaic Model


A mixed composition or a mosaic of phospholipids, glycolipids, sterols and proteins.



Transport Proteins


Passively let specific solutes diffuse through a menbrene-spanning channel in their interior or actively pump them through.

Recetor Proteins

Are designed so special molecules can bind to them, and send messages to the cell that trigger some sort of reaction within the cell.




Recognition Proteins



Indentify the type of substances that enter the cell.




Adhesion Proteins

Join cells to form a tissue.



Comunication Proteins

Comunicate a cell to another






Diffusion


The process by which molecules spread from areas of high concentratiion, to areas of low concentration. When the molecules are even throughout a space






Electric Gradient


Is a spatial variation of both electrical potential and chemical concentration across a membrane.



Pressure Gradient

 Is a physical quantity that describes in which direction and at what rate the pressure changes the most rapidly around a particular location.




Osmosis

 Is the movement of solvent molecules through a selectively-permeable membrane into a region of higher solute concentration, aiming to equalize the solute concentrations on the two sides.


Hypotonic Solution



 Is the same as the solute concentration of another solution with which it is compared.




Hypertonic Solution
 Is a solution having a lesser solute concentration than the cytosol.




Isotonic Solution
Solutions that have equal osmotic pressure, such as the isotonic environment.




Hydrostatic Pressure

 Is the pressure exerted by a fluid at equilibrium due to the force of gravity.




Osmotic Pressure

Is the pressure which needs to be applied to a solution to prevent the inward flow of water across a semipermeable membrane.

Endocytosis


A small patch of plasma menbrane balloons inward and pinchesoff inside the cytoplasm.


Exocytosis

A vesicle moves to the cell surface, and then the protein-studded lipid bilayer of  its menbrane.



Phagocytosis

("cell eating")   

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