User:Jimmyjohnslaser/sandbox

The italicized portions are the portions I have added.

In biology, a transporter is a transmembrane protein that moves ions (or other small molecules) across a biological membrane''. There are different types of transporters including, pumps, uniporters, antiporters, and symporters. Active transporters or Ion pumps are transporters'' that convert energy from various sources—including adenosine triphosphate (ATP), sunlight, and other redox reactions—to potential energy by pumping an ion up its concentration gradient. This potential energy could then be used by secondary pumps to drive vital cellular processes, such as ATP synthesis .

''This page is focused mainly on transporters acting as pumps, but transporters can also function to move molecules through Facilitated diffusion. Facilitated diffusion does not require ATP and allows molecules, that are unable to quickly diffuse across the membrane (passive diffusion), to diffuse down their concentration gradient through these protein transporters.''

Ion transporters are essential for proper cell function and thus they are studying by researchers using a variety of methods. These methods will be mentioned as well in this article.

ATP Producing Transporter [edit]
ATP producing transporters run in the opposite direction of ATP Utilizing transporters. These proteins transport ions from high to low concentration with the gradient but in the process ATP is formed. Potential energy in the form of the concentration gradient is used to generate ATP. In animals, this ATP synthesis takes place in the mitochondria using F- type ATPase otherwise known as ATP synthase. This process utilizes the electron transport chain in a process called oxidative phosphorylation. V-type ATPase serves the opposite function as F-type ATPase and is used in plants to hydrolyze ATP to create a proton gradient. Examples of this are lysosomes that use V-type ATPase acidify vesicles or plant vacuoles during process of photosynthesis in the chloroplasts. This process can be regulated through various methods such as pH.

Secondary transport[edit]
Secondary transporters also transport ions against the concentration gradient – from low concentration to high concentration - but unlike primary transporters which use ATP to create a concentration gradient, secondary transporters use the potential energy from the concentration gradient created by the primary transporters to transport ions. ''For example, the sodium-dependent glucose transporter found in the small intestine and kidney use the sodium gradient created in the cell by the sodium potassium pump (as mentioned above) to help carry glucose into the cell. This happens as sodium flows down its concentration gradient which provides enough energy to push glucose up its concentration gradient back into the cell. This is important in the small intestine and the kidney to prevent them from losing glucose. Symporters, such as the sodium glucose transporter and'' the Sodium-chloride symporter, transport an ion with its concentration gradient, and they couple the transport of a second molecule in the same direction. Antiporters also use the concentration gradient but the coupled molecule is transported in the opposite direction.

Patch Clamp
A patch clamp is an electrophysiology technique used to study channels and transporters in cells.

Planar Lipid Bilayer Experiments[edit]
'These experiments are a type of voltage clamp used to study ion channels' in artificial membranes using electrophysiology. The channels are inserted into the artificial membrane with a micellar solution or with liposomes. These channels can then be tested in different environments. These experiments can help explain differences in transporter function in different environments due to membrane pressure.'

FRAP
Fluorescence after photobleaching (FRAP) is a technique used to track diffusion of lipids or proteins in a membrane. This technique is used to better understand where certain transporters are in the cell and their mobility in the cell.

FRET-
Förster resonance energy transfer (FRET) is a technique that uses fluorescence to track how close two proteins are to each other. This has been used in studying transporters to see how they interact with other cellular proteins.

X-ray Crystallography
X-ray crystallography is an incredible tool that allows the structure of proteins to be seen, though it is only a snapshot of one protein conformation. The structure of transport proteins allows researchers to further understand how and what the transporter does.