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Mechanism of Transportation in a cell

Or. Mechanism of Transportation in a cell. Transportation of molecules in a cell Presentation by: Mahendra Kandel Email: mahendrakandel10@gmail.com For: Bachelor of Pharmacy, NIST Date: December 31, 2012. Functions of Cell Membrane. 1. Protect cell

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Mechanism of Transportation in a cell

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  1. Or Mechanism of Transportation in a cell Transportation of molecules in a cell Presentation by: Mahendra Kandel Email: mahendrakandel10@gmail.com For: Bachelor of Pharmacy, NIST Date: December 31, 2012 presentation by: Mahendra Kandel

  2. Functions of Cell Membrane 1. Protect cell 2. Control incoming and outgoing substances 3. Maintain ion concentrations of various substances 4. Selectively permeable - allows some molecules in, others are kept out presentation by: Mahendra Kandel

  3. Phospholipid Bilayer presentation by: Mahendra Kandel

  4. Structure of the Cell Membrane Outside of cell Carbohydrate chains Proteins Lipid Bilayer Transport Protein Phospholipids Inside of cell (cytoplasm) presentation by: Mahendra Kandel Go to Section:

  5. The Selectively Permeable Nature of Cell Membranes presentation by: Mahendra Kandel

  6. Membrane Proteins • Each type of protein in a membrane has a special function • Adhesion proteins – hold to surface, cells • Receptor proteins – receive messages • Enzymes – speed up reactions • Transport proteins (active and passive) active – require energy to transport passive – no energy required for transport presentation by: Mahendra Kandel

  7. Concentration and Gradients • Concentration • The number of molecules (or ions) of substance per unit volume of fluid • Concentration gradient • The difference in concentration between two adjacent regions • Molecules always move from a region of higher concentration to one of lower concentration presentation by: Mahendra Kandel

  8. Types of Transportation • Passive Transport • Active Transport • Endocytosis (phagocytosis & pinocytosis) • Exocytosis presentation by: Mahendra Kandel

  9. Passive Transport • No energy required • Move due to gradient • differences in concentration, pressure, charge • Move to equalize gradient • High moves toward low presentation by: Mahendra Kandel

  10. Weeee!!! high low Passive Transportation presentation by: Mahendra Kandel

  11. Types of Passive Transport 1. Diffusion 2. Osmosis 3. Facilitated diffusion presentation by: Mahendra Kandel

  12. Diffusion • Movement of molecules from an area of high concentration to an area of low concentration. • Movement from one side of a membrane to another, un-facilitated presentation by: Mahendra Kandel

  13. Diffusion • Molecules move to equalize concentration presentation by: Mahendra Kandel

  14. Diffusion presentation by: Mahendra Kandel

  15. Osmosis • Special form of diffusion • Fluid flows from lower solute concentration • Often involves movement of water • Into cell • Out of cell presentation by: Mahendra Kandel

  16. Osmosis presentation by: Mahendra Kandel

  17. Tonicity is a relative term • Hypotonic Solution - One solution has a lower concentration of solute than another. • Hypertonic Solution - one solution has a higher concentration of solute than another. • Isotonic Solution - both solutions have same concentrations of solute. presentation by: Mahendra Kandel

  18. Solution Differences in a tissue/cells • solvent + solute = solution • Hypertonic • Solutes in cell more than outside • Outside solvent will flow into cell • Isotonic • Solutes equal inside & out of cell • Hypotonic • Solutes less than outside cell • Fluid will flow out of cell presentation by: Mahendra Kandel

  19. presentation by: Mahendra Kandel

  20. Facilitated Diffusion • Differentially permeable membrane • Channels (are specific) help molecule or ions enter or leave the cell • Channels usually are transport proteins • No energy is used presentation by: Mahendra Kandel

  21. Types of Transport presentation by: Mahendra Kandel

  22. Process of Facilitated Transport • Protein binds with molecule • Shape of protein changes • Molecule moves across membrane presentation by: Mahendra Kandel

  23. This is gonna be hard work!! high low Active Transport • Molecular movement • Requires energy (against gradient) • Example is protein pump presentation by: Mahendra Kandel

  24. Protein Pumps -transport proteins that require energy to do work • Example: Sodium / Potassium Pumps are important in nerve responses. presentation by: Mahendra Kandel

  25. FLUIDOUTSIDECELL Phosphorylated transport protein Transportprotein • Active transport in two solutes across a membrane • Na+/K+ pump • Protein shape change Firstsolute 1 First solute, inside cell, binds to protein 2 ATP transfers phosphate to protein 3 Protein releases solute outside cell Second solute 4 Second solute binds to protein 5 Phosphate detaches from protein 6 Protein releases second solute into cell presentation by: Mahendra Kandel Figure 5.18

  26. Sodium-Potassium Pump presentation by: Mahendra Kandel

  27. Endocytosis • Movement of large material • Particles • Organisms • Large molecules • Movement is into cells • Types of endocytosis • bulk-phase (nonspecific) • receptor-mediated (specific) presentation by: Mahendra Kandel

  28. Bulk-phase endocytosisExtracellular fluid is captured in a vesicle and brought into the cell; the reverse of exocytosis • Receptor-mediated endocytosis • Specific molecules bind to surface receptors, which are then enclosed in an endocytic vesicle presentation by: Mahendra Kandel

  29. Process of Endocytosis • Plasma membrane surrounds material • Edges of membrane meet • Membranes fuse to form vesicle presentation by: Mahendra Kandel

  30. presentation by: Mahendra Kandel

  31. Forms of Endocytosis • Phagocytosis – cell eating • Pinocytosis – cell drinking presentation by: Mahendra Kandel

  32. Exocytosis • Reverse of endocytosis • Cell discharges material presentation by: Mahendra Kandel

  33. Exocytosis • Vesicle moves to cell surface • Membrane of vesicle fuses • Materials expelled presentation by: Mahendra Kandel

  34. Summary of Methods of Transport Across Membranes 1. Diffusion -passive transport - no energy expended 2. Osmosis - Passive transport of water across membrane 3. Facilitated Diffusion - Use of proteins to carry polar molecules or ions across 4. Active Transport- requires energy to transport molecules against a concentration gradient – energy is in the form of ATP presentation by: Mahendra Kandel

  35. Thank you! presentation by: Mahendra Kandel

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