BIOL 1201 Chapter : Ch 7 Outline
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>>>>>membrane structural models have evolved as new data is acquired. Hydrophilic zones = polar head groups + globular proteins. About 8 mm thick: confirmed in 1950"s, problems with this model: Hydrophilic zones = polar head groups + hydrophilic portion of proteins. Hydrophobic zone = 2 x hydrophobic tails + hydrophobic portion of. Singer and nicolson: fluid-mosaic model (see fig 7. 3) Confirmed by freeze-fracture and freeze-etch micrographs (see fig 7. 4) Lipid concentration (saturated/unsaturated fatty acid tails) and temperature depend on each other. Mosaic: mosaic aspect of membranes means that there are proteins interspersed within the lipid bilayer, a membrane is a fluid mosaic of lipids, proteins, and carbohydrates. Proteins as the mosaic of the cell membrane. A mosaic of different proteins are embedded in the lipid bilayer. These proteins have two types of spacial arrangements. Membranes have a bifacial orientation (i. e. sidedness) (see fig 7. 12: have cytoplasmic side and non-cytoplasmic side.
