Peripheral membrane proteins
Proteins stuck to the surface of the membrane bilayer. Can help to maintain structure of membrane-bound organelles / Easier to separate from membranes, Proteins that do not interact with the hydrophobic interior of the phospholipid bilayer; noncovalently bind to regions of integral membrane proteins that project out from the membrane; typically bound to the membrane by hydrogen and/or ionic bonds
A protein at least partly embedded in the bilayer. They have both hydrophilic and hydrophobic regions.
Proteins with short chains of sugars attached to them; in eukaryotic cells they are important membrane proteins that allow cell-cell recognition and interaction. Binding of glycoproteins causes cell adhesion.
Consists of a carbohydrate covalently bonded to a lipid. In eukaryotes, found extracellularly and involved with tissue recognition, eg ABO blood group markers.
Phospholipids are a class of lipids and are a major component of all cell membranes as they can form lipid bilayers. Most phospholipids contain a diglyceride, a phosphate group, and a simple organic molecule such as choline; one exception to this rule is sphingomyelin, which is derived from sphingosine instead of glycerol. The first phospholipid identified as such in biological tissues was lecithin, or phosphatidylcholine, in the egg yolk, by Theodore Nicolas Gobley, a French chemist and pharmacist, in 1847.
Typically a transmembrane protein with hydrophobic regions that extend into and often completely span the hydrophobic interior of the membrane and with hydrophilic regions in contact with the aqueous solution on either side of the membrane (or lining the channel in the case of a channel protein).
A process of random movement towards a state of equilibrium. In effect, it is a net movement from regions of greater concentration to regions of lesser concentration.
Diffusion of water across membranes.
The spontaneous passage of molecules and ions, bound to specific carrier proteins, across a biological membrane down their concentration gradients.
a transmembrane protein channel that allows a specific ion to flow across the membrane down its concentration gradient
A molecule that binds specifically to a receptor site of another molecule.
The movement of a substance across a biological membrane against its concentration or electrochemical gradient with the help of energy input and specific transport proteins.
Primary active transport
Involves the hydrolysis of ATP into ADP which provides the required energy fro transpost
Secondary active transport
Does not directly use ATP. Instead, its energy is supplied by an ion cencentration gradient or and electrical gradient. This transport system uses the enrgy of ATP to set up that system.