Passive and Active Transport


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  • Passive and Active Transport

    1. 1. Passive and Active Transport FOS 3 Infectious Disease Unit
    2. 2. Homeostasis <ul><li>When organisms adjust internally to changing external environments </li></ul><ul><li>One way to maintain homeostasis is by controlling the movement of substances across the cell membrane. </li></ul>
    3. 3. Transport Across Membranes Active transport is pumping against the concentration gradient
    4. 4. 3 types of Passive Transport <ul><li>Diffusion, Osmosis and Facilitated Diffusion </li></ul>
    5. 5. Diffusion <ul><li>Diffusion is movement from an area of high concentration to low concentration </li></ul><ul><li>Diffusion is passive transport: NO energy is required! </li></ul>
    6. 6. Passive Transport- Diffusion <ul><li>Oxygen, Carbon dioxide, water and amino acid molecules are small enough to diffuse. </li></ul><ul><li>Proteins, carbohydrates, and other ions are too large to diffuse. </li></ul>
    7. 7. Passive Transport-Diffusion
    8. 8. Passive Transport
    9. 9. Simple Diffusion Across Bilayers
    10. 10. Passive Transort- Osmosis More water Less water
    11. 11. Osmosis: Water down Conc. Gradient
    12. 12. Tonicity More solute in than out
    13. 13. Passive Transport- Facilitated Diffusion <ul><li>Some ions diffuse through channel proteins. The pores can always be open or open in response to a stimulus. No energy is required so this is still passive transport. </li></ul>
    14. 14. Passive Transport- Facilitated Diffusion
    15. 15. Passive Transport- Facilitated Diffusion
    16. 16. Passive Transport- Facilitated Diffusion <ul><li>Transport of substances through the cell membrane down a concentration gradient aided by carrier or channel proteins. </li></ul>
    17. 17. Active Transport <ul><li>Transport against the concentration gradient that requires energy </li></ul>
    18. 18. Active Transport: Sodium-Potassium Pump
    19. 19. Electrochemical Gradient <ul><li>An electrochemical gradient is a concentration gradient with ions: </li></ul><ul><ul><li>These ions want to move down their concentration gradient </li></ul></ul><ul><ul><li>These ions also want to move towards the opposite charge found on the other side of the membrane. </li></ul></ul><ul><ul><li>This attraction for the other side of the membranes (membrane potential) can be harnessed to do work. </li></ul></ul>
    20. 20. Active Transport- Electrogenic Pump
    21. 21. Active Transport- Cotransport
    22. 22. Movement “Across” Membrane <ul><li>Endocytosis and Exocytosis </li></ul><ul><li>These are mechanisms that involve movement into and out of the lumen of the endomembrane. </li></ul><ul><li>NOT movement directly across the membrane </li></ul><ul><li>Substances enter the endomembrane system but not the cytoplasm! </li></ul>
    23. 23. Endocytosis <ul><li>Phagocytosis </li></ul>Taking up solids Allows digestion in confined space
    24. 24. Phagocytosis Pictures
    25. 25. Exocytosis
    26. 26. Hormones <ul><li>Chemicals secreted by cells that act to regulate the activity of other cells in the body. </li></ul><ul><li>Four Functions: </li></ul><ul><ul><li>Regulate processes, like growth and development </li></ul></ul><ul><ul><li>Coordinate production, use and storage of energy. </li></ul></ul><ul><ul><li>Maintaining Homeostasis </li></ul></ul><ul><ul><li>React to stimuli outside the body </li></ul></ul>
    27. 27. Hormones <ul><li>Two types: </li></ul><ul><ul><li>Amino Acid Hormones </li></ul></ul><ul><ul><li>Steroid Hormones </li></ul></ul><ul><ul><ul><li>Lipid hormones </li></ul></ul></ul>
    28. 28. Hormones- Amino Acid <ul><li>How they work: </li></ul><ul><ul><li>Bind to a receptor protein on the Cell Membrane, the receptor membrane changes shape </li></ul></ul><ul><ul><li>The shape changes causes a second messenger which causes a change in the target cell </li></ul></ul>
    29. 29. Hormones-Steroid Hormones <ul><li>How it works: </li></ul><ul><ul><li>Steroid Hormone is release, it diffuses through the cell membrane </li></ul></ul><ul><ul><li>There is a hormone receptor in the cytoplasm. The hormone and receptor bind </li></ul></ul><ul><ul><li>The hormone receptor complex enters the nucleus and either activates or inactivates transcription of a gene. </li></ul></ul>