KINE 2011 Lecture Notes - Lecture 8: Membrane Transport, Osmotic Pressure, Electrochemical Gradient

• School: York University
• Department: Kinesiology & Health Science
• Course: KINE 2011
• Professor: Ali Abdul Sater

Document Summary

Notions of membrane permeability , impermeability, selective permeability. 2 properties influence whether a substance can permeate the plasma membrane without any assistance. Unassisited membrane transport: molecules that can penetrate the plasma membrane by two forces, diffusion down a concentration gradient, movement along an electrical gradient, 1. Ions are electrically charged; in addition to concentration gradients (chemical), their movement is effected by their electrical charge. Tonicity: the effect of the solution on cell volume: determined by the concentration in non-penetrating solutes (the penetrating ones are equally distributed between ecf and icf) Hypotonic: tend to shrink the cell: outside to inside of the cell. Osmolarity: the measure of solute concentration per unit of solvent: not the same as tonicity, takes into account all solute concentration. Iso-osmotic, hypo-osmotic, hyper-osmotic: osmolarity involves total amount of solutes present, molarity involves concentration of the compound as a whole, ex. Nacl once dissolved in water separates into its ions as na+ and cl-