Lecture 3- cell membranes

Lecture 3 cell membranes

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: "(not" actually"a"membrane) 10:25 Gardiner 2013 Fig. 5.5 7 !Which"structure"forms"depends"on"the"phospholipid" concentration !Polar"hydrophillic""heads""are"in"the"aqueous"solution" (associate"with"water) !Nonpolar"hydrophobic"fatty"acid""tails""are"not"in"the" aqueous"environment !This"positioning"occurs"due"to"the"hydrophobic"effect!" the"tendency"of"polar"molecules"to"exclude"hydrophobic" molecules - Freeze Fracture- freeze cells in liquid nitrogen and use a sharp knifes edge to fracture the cells by hitting them HOW WILL WE STUDY MEMBRANES? - The cells break along certain fracture lines (usually inner and outer halves) which tend to be where the phospholipid tails are - Breaking the cells exposes the membrane interior - End up with 2 surfaces- one with bumps, one with concavities that match the bumps - Individual particles the size of proteins are embedded - The particles visible in the expose membrane interior are integral membrane proteins Fig 5.3 - MEMBRANE ASYMMETRY- provides evidence that the two sides are distinctly different. The membranes proteins found on one half of the bilayer are structurally and functionally distinct from those of the other half 3 • In 1972, S.J. Singer and G. Nicolson – model that proposed that the membrane proteins are dispersed and individually inserted into the phospholipid bilayer. – In this fluid mosaic model, the hydrophilic regions of proteins and phospholipids are in maximum contact with water and the hydrophobic regions are in a nonaqueous environment. 10:25 Gardiner 2013 !Proposed&that&proteins&are&embedded&in&a& phospholipid&bilayer !Suggested&that&the&exterior&parts&must&be&hydrophillic...
View Full Document

This note was uploaded on 02/11/2014 for the course BIO 1202B taught by Professor Almanke during the Winter '12 term at UWO.

Ask a homework question - tutors are online