What is medicated permeability? discuss the type of mediated permeability
Answers
type of mediated permeability are;
evaporation
hot air
disploplastic
Permeability of biological membranes for many substances is altered by transport molecules which are located in the membrane. This phenomenon is called Mediated permeability. If two molecules have a similar size, shape, structure and lipid solubility, it is expected that the membrane will have similar permeability values for both the molecules, and therefore the flux will be similar for both molecules at a given concentration gradient. But this may not be true in many cases. For example, Glucose and Galactose (two isomers) have the same size and shape and the structures are very similar to each other. The two molecules have no charge but have similar values of lipid solubility. Yet, glucose is transported much faster than galactose by human RBC, because the membrane of RBC has much higher specificity for glucose than for the galactose. There are some specialized molecules located in the membrane that help in transporting glucose molecules faster across the membrane. These are called transport molecules, glucose and not galactose, is transported preferentially because a transport molecule is very specific in reorganization to its substrate. This type of transport phenomenon is known as mediated permeability.
There are two main types of mediated permeability: Facilitated diffusion and active transport.
Facilitated diffusion is a passive diffusion in which the molecule in transport across the membrane from the higher concentration to lower concentration side. But it requires transport molecules. The membrane is practically impermeable in the absence of transport molecules. Facilitated diffusion does not obey Fick’s law. Active transport process is a mediated permeability in which the molecule moves from low concentration to high concentration (against the concentration gradient) ATP are required in active transport.
Active transport is commonly known as pump. Active transport of H+ is called proton pump. Active transport processes provide for creation and maintenance of concentration gradients. Which are essential for the proper functioning of the cell.
In the shuttle processes, the substance is converted to a second substance which is transported to the other side of the membrane by facilitated diffusion or active transport.