Transport different molecules inside and out of the cell or intracellular organelle
What are the functions of the membrane?
Maintain cell potential
Provide sites for maintaining the intactness of the cells
What are examples of lipid components of biological membranes?
(T/F) Phospholipids in the membrane diffuse freely along the layer.
(T/F) Sphingolipids form the outer leaflet of the plasma membrane.
True. The layer is mechanically and chemicall stable which is belived to play a protective role.
What are lipid rafts?
Cholesterol interacts with fatty acid tails of phingolipids serving as "glue" to hold the raft together. Some proteins associate preferably with lipid rafts and the components are held together by weak interactions, there is rapid exchange of lipids and proteins between lipid rafts and the surrounding membrane.
What does loss of lipid asymmetry across the membrane indicate?
Exposure of phosphatidylerine in the outerpart of the bilayer is a signal for programmed cell death (apoptosis)
In red blood cells, phosphatidylserine is important for blood clot formation.
What are the three types of lipid-translocating proteins?
What are Flippases?
ATP-dependent lipid translocating proteins that catalyze the transport of the lipds from the outer to the inner leaflet against the concentration gradient.
What are floppases?
ATP-dependent lipid-translocating proteins that transport substrates from the inner membrane to the external part of the membrane.
What are scramblases?
Lipid-translocating proteins that are nonspecific bidirectional lipid translocases.
They transport along the concentration gradient
What are the three types of lipid-linked proteins?