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Ch 7: Membrane Structure and Function

History: Early research into membranes & lipid films C. E. Overton (1895)

Agnes Pockels (1891) Irving Langmuir (1917)

“Langmuir trough”

Evert Gorter & F. Grendel

Hugh Davson

James Danielli

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S. Jonathan Singer & Garth Nicholson’s fluid mosaic model

(Data from freeze-fracture)

More current and detailed representation

Cell fusion studies: Protein movements

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Membrane lipid movement & composition

others use other molecules, eg: sterols, hopanes, etc.

Movement of membranes inside of a cell

Animal cell membrane: proteins

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Membrane protein functions

Animal cell membrane: carbohydrate

http://www.youtube.com/watch?v=VY0mZUDvbH4

Diffusion

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Dialysis: movement of materials through a semi-permeable membrane

Osmosis: movement of water through a semi-permeable membrane

time

(on both sides)

Tonicity

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Chemistry Nobel 2003, Peter Agre: aquaporins

Active transport: eg: sodium-potassium pump (an electrogenic pump in animals)

-

+ (overall)

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Another electrogenic pump: proton pump (in plants, fungi, bacteria)

Cotransport eg: proton-coupled transport of sucrose (in plant leaves)

Movement of membranes inside of a cell:

Exocytosis (sometimes called secretion)

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Movement of membranes inside of a cell: Endocytosis:

Movement of membranes inside of a cell: Endocytosis:

Movement of membranes inside of a cell: Endocytosis:

recycling of lipids & receptors

recycling of clathrin

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An interesting place to look at for more related to this info (see Membranes & Energy): http://virtuallaboratory.colorado.edu/Biofundamentals-2014/