BABS1201 Lecture Notes - Lecture 6: Lipid Bilayer, Cytoskeleton, Cytosol
17 May 2018
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Department
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BABS1201
19TH MARCH 2018
MAINTAINING CELL INTEGRITY
COMPREHEND THE STRUCTURE OF CELL MEMBRANES AND THEIR FUNCTION IN MAINTAINING CELL INTEGRITY
× Davson-Danelli model proposed in 1935: a kind of ‘sandwich’ consisting of the phospholipid
bilayer in between two layers of peripheral membrane proteins
× Fluid-Mosaic model proposed by Singer and Nicholson in 1972 which shows a phospholipid
bilayer with various peripheral membrane proteins floating around within it (held in place
by the cytoskeleton) in addition to the integral membrane proteins which are embedded in
the membrane- the ‘fluid’ represents how some parts of the membrane can move around
freely, if they are not attached to other parts of the cell
× The cytoskeleton binds to the peripheral protein to help maintain the structure of the
membrane
× Cholesterol helps to strengthen the lipid bilayer and decrease its permeability
× Carbohydrates, or sugars which are attached to proteins or lipids
× NOTE: looking carefully at the image below, it can be seen that carbohydrates are only
shown on one side of the structure- the side which faces the extracellular environment,
whilst peripheral proteins are shown on the other side of the structure, which typically
faces the cytosol, the intracellular space inside the cell
× The position of the protein domains relative to the membrane is fixed after the protein is
inserted into the plasma membrane
Document Summary
Comprehend the structure of cell membranes and their function in maintaining cell integrity. Davson-danelli model proposed in 1935: a kind of sandwich" consisting of the phospholipid bilayer in between two layers of peripheral membrane proteins. The cytoskeleton binds to the peripheral protein to help maintain the structure of the membrane. Cholesterol helps to strengthen the lipid bilayer and decrease its permeability. Carbohydrates, or sugars which are attached to proteins or lipids. The position of the protein domains relative to the membrane is fixed after the protein is inserted into the plasma membrane. The plasma membrane has distinct cytoplasmic and extracellular faces. The extracellular face is topologically equivalent to the inside face of the er, golgi, lysosome and vesicle membranes. Proteins and lipids do not easily flip from one side of the membrane to the other. To describe the different components of the cell membrane that play an important role in.
