Cell membranes Structure based on hydrophilic-hydrophobic interaction of phospholipids(磷脂) with aqueous phases Contain approx 50 protein whose function is probably mostly transport
Cell membranes • Structure based on hydrophilic-hydrophobic interaction of phospholipids (磷脂）with aqueous phases • Contain approx. 50 % protein whose function is probably mostly transport
Cell membranes are highly selective The basic structure of a cell membrane is the hospholipid bilayer, which has very low permeability to most nutrients Uptake is made faster by transport proteins embedded in the membrane 时m
Cell membranes are highly selective The basic structure of a cell membrane is the phospholipid bilayer, which has very low permeability to most nutrients. Uptake is made faster by transport proteins embedded in the membrane
Permeability of membrane high permeability to molecules that are gases e.g. O2, CO2 lipid soluble e. g. ethanol non-polar e.g. urea low permeability to ions e.g. K+, NO3- very low permeability to divalent ions e. g Mg2+, SO42
Permeability of membrane • high permeability to molecules that are: gases e.g. O2 ,CO2 • lipid soluble e.g. ethanol • non-polar e.g. urea • low permeability to ions e.g. K+ , NO3 - • very low permeability to divalent ions e.g. Mg2+, SO4 2-
MEMBRANE PERMEABILITY Lipid Bilayer cms、 Biological Memb 102 H2o H2O Ethano→ 10 Ethano乙醇 Boron→ 10-6 ← Boron K+ 10-8 c Na c 10-10 K Na 二
10-2 10-4 10-6 10-8 10-10 P cm/s ClK+ Na+ H2O Ethanol Boron ClK+ Na+ Boron H2O Ethanol乙醇 Lipid Bilayer Biological Membrane MEMBRANE PERMEABILITY
Permeability of membrane 带电荷的 气体 小的不带电荷极性分子离子大的不带电荷 的极性分子 Charged 极性分子 ases Small uncharged polar molecules ·CO2 polar molecules . amino acid ·K·Mg2,Ca arge uncharged Water cr, HCO3 polar molecules H2O ethanol glucose 6-Phosphate HiPO4 ③像线使得线 lipid bila
气体 小的不带电荷 的极性分子 带电荷的 极性分子 离子 大的不带电荷 极性分子 Membrane permeability Permeability of membrane