Table 10-1 Approximate Lipid Compositions of Different Cell Membranes PERCENTAGE OF TOTAL LIPID BY WEIGHT LIVER CELL RED BLOOD MYELIN MITOCHONDRION ENDOPLA SMIC E COLI PLASMA CELL PLASMA (NNER AND RETICULUM BACTERIUM LIPID MEMBRANE MEMBRANE OUTER MEMBRANES Cholesterol 23 22 Phosphatidylethanolamine 7 18 15 28 17 70 Phosphatidylserine 2 5 trace Phosphatidylcholine 24 40 Sphingomyelin 19 18 trace trace Others 22 13
3 polar head groups 2 cholesterol- stiffened region more fluid realon 0 Figure 10-5 Molecular Biology of the Cell(@ Garland Science 2008)
Figure 10-5 Molecular Biology of the Cell (© Garland Science 2008)
shape of lipid packing of lipid molecule molecules lipid micelle water 0099900 pl bilayer 0000000 Figure 10-3. a lipid micelle and a lipid bilayer seen in cross-section. Lipid molecules form such structures spontaneously in water. The shape of the lipid molecule determines which of these structures is formed Wedge-Shaped lipid molecules(above) form micelles, whereas cylinder shaped phospholipid molecules(below) form bilayers
Figure 10-3. A lipid micelle and a lipid bilayer seen in cross-section. Lipid molecules form such structures spontaneously in water. The shape of the lipid molecule determines which of these structures is formed. Wedge-shaped lipid molecules (above) form micelles, whereas cylindershaped phospholipid molecules (below) form bilayers
water 00000 00●0 water 0000000 25 nm
water water lipid bilayer(black membrane