Cells (Transport)

I. Introduction
   
     A. Materials must pass through membranes.
   
          1. Water
   
          2. Nutrients
   
          3. Wastes
   
          4. Other
   
     B. How do they pass through membranes?
   
          1. Pores
          2. Simple Diffusion
          3. Facilitated Diffusion
          4. Active Transport
          5. Osmosis
          6. Endocytosis
          7. Exocytosis
   
II. Pores
   
     1. Nuclear Pores
   
     2. Cell Junctions
   
III. Simple Diffusion
   
     A. Along a concentration gradient
   
          1. The movement of material from an area
               of high concentration of that material
               to an area of low concentration of that
               material.
   
   
   
     B. Requires no energy expenditure by
          the cell
   
          1. Kinetic Energy
   
          2. Equilibrium
   
IV. Facilitated Diffusion
   
     A. Carrier-mediated movement along a
          concentration gradient
   
     B. Requires no energy expenditure by
          the cell
   
     C. Requires carrier proteins
   
          1. Transporter Proteins [Permeases]
   
               a. The Carriers
   
          2. Ligands
   
               a. The Carried
   
V. Active Transport
   
     A. Carrier-mediated movement against a
          concentration gradient
   
     B. Requires energy expenditure by the cell
   
     C. Requires carrier proteins
   
     D. Uses membrane pumps
   
          1. Sodium-Potassium Pump
               [Na+/K+-ATPase Pump]
   
               a. Pumps sodium (Na+) out of the cell
   
               b. Pumps potassium (K+) into the cell
   
          2. Calcium Pump
   
               a. Pumps calcium (Ca2+) out of the cell
   
          3. Proton Pump
   
               a. Pumps protons (H+) across membranes
   
VI. Osmosis
   
     A. Diffusion of Water through a
          Semipermeable Membrane
   
          1a. The movement of water (a solvent)
               from an area of high concentration of
               water to an area of low concentration
               of water across a semipermeable
               membrane; or…
   
          1b. The movement of water (a solvent)
               from an area of low concentration of
               solute to an area of high concentration
               of solute across a semipermeable
               membrane.
   
     B. Requires no energy expenditure by
          the cell
   
     C. Some Definitions and Examples
   
          1. Solvent
   
          2. Solute
   
          3. Solution
   
          4. Isotonic Solutions
   
   
   
          5. Hypotonic Solution
   
          6. Hypertonic Solution
   
   
   
          7. Osmotic Pressure
   
               a. Crenation

                    i) Plasmolysis (in plants)

   
    
           b. Lysis
   
                    i) Hemolysis
   
   
   
          8. Dialysis
   
VII. Endocytosis
   
     (Uptake of materials by the cell.)
   
     A. Phagocytosis
   
          1. "Cell Eating"
   
          2. The taking in of large particles by the cell.
   
          3. Vacuoles
   
               a. Lysosomes
   
   
   
     B. Pinocytosis
   
          1. "Cell Drinking"
   
          2. The taking in of liquids by the cell.
   
          3. Pinocytotic Vesicle
   
VIII. Exocytosis
   
     (Release of materials by the cell.)
   
     A. Reverse of endocytosis
   
          1. Vesicles
   
   
   
IX. Summary

Page obtained from link at URL: http://www.ric.edu/faculty/jmontvilo/109.htm Prepared by Jerome A. Montvilo, Ph.D. for the use of his students. Copyright © by Jerome A. Montvilo. All rights reserved. Please send questions, comments, or suggestions to jmontvilo@ric.edu. Last updated 15 January, 2008