Tuesday, February 1, 2011
I'm about to diffuse the situation...
Passive transport can be further subdivided into simple diffusion, osmosis, facilitated diffusion, and filtration. Simple diffusion is the passing of substances through the lipid bi layer along the concentration gradient without the use of a membrane protein. Facilitated diffusion differs in that a trans-membrane protein acts to "carry" the substance through the lipid bi layer via conformational changes protein. Osmosis is the movement of water through fluid filled channels, or aquaporins from an area of lower relative solute concentration to an area of higher solute concentration, until osmotic equilibrium is reached, where the relative concentration of solutes is equal on each side of the membrane. Filtration makes use of a pressure gradient, which acts to allow for selective passage by allowing only some particles through the channel. This especially useful in organs like the kidneys, which are responsible for filtering waste from our bodies.
Active transport is the movement of a substance against the concentration gradient, and makes use of specific transport proteins. Active transport may be primary, as with the sodium-potassium-ATPase "pump", of secondary, like the SGLT transporter, which relies on the energy created by diffusion of sodium to allow the passage of glucose as sort of a hitchhiker.
Both of these types of transport combine to provide antagonistic, and cooperative effects that are essential to sustaining life. One must remember, that sometimes the smallest things are responsible for the most amazing processes.
In this blog, I attempted to "arouse and fulfil" by using a creative subject heading, and first line. I wanted to try to also speak to a more broad audience by eliminating a great deal of jargon, while still explaining an important concept. Lastly, I attempted to read my writing aloud, which when I was working in the lab didn't make me look the most sane, but I digress.