The Cell Membrane

The Cell Membrane - hydrophilic heads on the inner and...

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The Cell Membrane The cell membrane functions as a semi-permeable barrier, allowing a very few molecules across it while fencing the majority of organically produced chemicals inside the cell. Electron microscopic examinations of cell membranes have led to the development of the lipid bilayer model (also referred to as the fluid-mosaic model). The most common molecule in the model is the phospholipid , which has a polar (hydrophilic ) head and two nonpolar (hydrophobic ) tails. These phospholipids are aligned tail to tail so the nonpolar areas form a hydrophobic region between the
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Unformatted text preview: hydrophilic heads on the inner and outer surfaces of the membrane. This layering is termed a bilayer since an electron microscopic technique known as freeze-fracturing is able to split the bilayer. Phospholipids and glycolipids are important structural components of cell membranes. Phospholipids are modified so that a phosphate group (PO 4-) replaces one of the three fatty acids normally found on a lipid. The addition of this group makes a polar "head" and two nonpolar "tails"....
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The Cell Membrane - hydrophilic heads on the inner and...

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