BIOB10H3 Lecture : Lec notes

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limerhinoceros831

17 Jun 2011

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Protein mobility: some freely mobile: others have restricted mobility. Bound to the external ecm: studied by frap: fluorescence recovery after photo-bleaching: can not identify individual protein units. You don"t know if the individual proteins are moving or they are attached to something else. Membrane lipid mobility: phospholipids are small and make up the bilayer. They don"t, instead seem to move freely within a compartment but movement is restricted between compartments. Removing membrane skeletal components removes some barriers to movement. Membrane domains & cell polarity: membranes are rarely homogenous. Sperm: d istinct parts, continuous plasma membrane. Movement across pm: plasma membrane: the plasma membrane has two main functions www. notesolution. com. Allow necessary materials in: charged and polar molecules can"t pass through hydrophobic membrane easily, membranes must be selectively permeable, two means of movement across pm: Passively by diffusion from high to low concentration [can involve protein channel] Actively by energy-coupled process : energy driven protein pump.

Related Questions

The rough ER is the site of synthesis of many different classes of membrane protein. Some of these proteins remain in the ER, whereas others are sorted to compartments such as the Golgi apparatus, lysosomes, and the plasma membrane. One measure of the difficulty of the sorting problem is the degree of âpurificationâ that must be achieved during transport from the ER. Are proteins bound for the plasma membrane common or rare among all ER membrane proteins? A few simple considerations allow one to answer this question. In a typical growing cell that is dividing once every 24 hours, the equivalent of one new plasma membrane must transit the ER every day. If the ER membrane is 20 times the area of a plasma membrane, what is the ratio of plasma membrane proteins to other membrane proteins in the ER? (Assume that all proteins on their way to the plasma membrane remain in the ER for 30 minutes on average before exiting, and that the ratio of proteins to lipids in the ER and plasma membranes is the same.) PLEASE DUMB THIS DOWN

Do membrane proteins exhibit asymmetry in the plasma membrane similar to phospholipids? How about cholesterol?

violetcod35

1) What is photobleaching? How/ Why does it happen?

2) How has "Fluorescence recovery after photobleaching" (FRAP) been used to test the "fluid mosaic model" of membrane function?

3) Are there cases when membrane proteins are stationary?

BIOB10H3 Lecture : Lec notes

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