BIOL 205 Lecture Notes - Lecture 5: Membrane Transport Protein, Passive Transport, Semipermeable Membrane
Document Summary
Passive transport form of transport in which the molecules move from a region of high. Membrane transport concentration to a region of low concentration. Active transport a form of transport that move solutes across a membrane against their concentration gradient. Learning objective #1 given a set of molecules of differing solubility in water, predict their relative rates of diffusion across a membrane bilayer. Most molecules cannot simply diffuse across the plasma membrane: the smaller the molecule and the more hydrophobic, or nonpolar, it is, the more rapidly it will diffuse across the membrane. Learning objective #2 compare and contrast the properties and functions of channels and carriers. Channels water-filled pores through which substrates passively diffuse down their electrochemical gradient. Transporters they undergo a cycle of conformational changes linked to substrate binding and dissociation on opposite sides of the membrane. They transfer only those molecules or ions that fit into specific binding sites on the protein so these provide great specificity.
