Water flows in a vertical pipe of 0.15-m diameter at a rate of0.2 m3/s and a pressure of

Cell Bio How membrane control the traffic of small molecules such as ions and sugars into and out of the cell  Fig E13-3 o Transport processes within a composite eukaryotic cell  Table 11-1 o Concentrations of certain ions and sugars across the membrane  Fig 11-1 o Lipid bilayers are impermeable to solutes and ions o The smaller and less polar the molecule- the more rapidy it will diffuse across the membrane  Fig 11-3 o Transporters and channel proteins o Differ in the way they discriminate between the solutes  Fig E13-4 o Transporter  highly SPECIFIC for particular solutes (based on specific binding)  Shares kinetics with enzymatic reacitons  Undergoes a serious of conformational changes  Act like a turnstile instad of an open door o Ion channels  Highly selective (based on size and electrc chargE)  Forms a hydrophilic pore across the bilayer through which specific ions can diffure (narrow trapdoor with open/close conformation)  MUCH greater transport rate than transporter)  Fig 11-4a o Passive vs active transport o Simple diffusion: no transport protein involved- fat soluble o Facilitated diffusion: involves tranport proteins ions and most small molecules o Passive  Channel