Absorption of mineral substances from soil and transport of ions through cellular membranes. Diffusion

you are: Absorption of mineral substances from soil and transport of ions through cellular membranes

Ions can get through a membrane passively or actively that, possibly, occurs in different sites of a membrane. Ions, diffundirujushchie through a membrane in that and other direction, move thanks to own kinetic energy, without consuming in this process ATR, other connections rich with energy. ability of some kinds of molecules to get through cellular membranes is connected with their solubility in lipidah. As small lipido soluble molecules pass through membranes faster, than larger, sites through which there is such moving, obviously, is better it is possible to present in the form of small lipidnyh the channels crossing a membrane. Though inorganic ions are not dissolved in lipidah, they too can get through a membrane. Recently the data is obtained, allowing to assume that inorganic ions pass through a membrane on the water albuminous channels which have received the name permeaz.

One ions diffundirujut through a membrane much faster than others that testifies to ionic specificity permeaz. The factor of permeability R describes relative ability of various ions diffundirovat through a membrane at comparable standard gradients. as the majority of membranes more pronitsaemo for To +, than for other ions, value R for To + is conditionally accepted for 1,0. Seaweed Nitella factors of permeability for Na + and С1_ are equal In huge cages accordingly 0,18 and 0,033. From bacteria and mushrooms have been allocated polipeptidy and the fibers, capable to form corresponding channels for certain ions. Such substances named ionoforami, at addition to artificial lipidnym to membranes cause increase in speed of diffusion of the given ion a million times. as similar connections break normal selective permeability of membranes, they can represent itself as antibiotics, killing certain kinds of cages. The antibiotic gramitsidin, considered earlier, concerns connections of this type.