The phagocytosis and pinocytosis

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2. PHAGOCYTOSIS AND PINOCYTOSIS

3. Passive Transport High -> Low Concentration No ATP needed Towards equilibrium Simple diffusion Facilitated diffusion Transport proteins Ion channels Osmosis Active Transport Low -> High Concentration ie;Against concentration gradient ATP needed Cell membrane pumps Transport proteins Ion channels Movement in vesicles Endocytosis Pinocytosis Phagocytosis Exocytosis Modes of fluid transport

4. PHaGOCYTOSIS

5. Pasteur’s ; Elie Metchnikoff ,Russian Zoologist in 1883 first recognized PHAGOCYTES

6. TWO PRINCIPAL CLASSES OF PHAGOCYTOSIS Polymorphonuclear granulocytes ( polymorphos ) Produced in bone marrow and discharged into blood 50 to 100 billion polymorphous Live for a few days only Contain numerous enzyme Membrane - bound organelles called LYSOSOMES

7. Macrophages Precursor monocytes (blood cells with horse shoe shaped nuclei Live for a long time They are not numerous as polymorphous

8. STEPS

9. Killing mechanisms of phagocytes . The figure shows the many different techniques used by phagocytes to kill pathogens. Some require oxygen while others do not

10. Capture of a Yeast Cell (yellow) by Membrane Extensions of an Immune System Cell (blue)

11. Pinocytosis- sipping. Taking in of liquid droplets by formation of pinocytic vesicles or pinosomes. Vesicles formed are often small( micropinotic vesicles) -Micro pinocytosis 1 st observed by Edwards in amoeba and by lewis in cultured cells Eg : Amoeba

12. Plasma membrane of such cell invaginates forming a pinocytic channel . The channel is then cut off from the plasma membrane to give a pinocytic vesicle . Lysozome approaches and carries out intracellular digestion as mentioned in phagocytosis.

13. Key features of Phagocytosis and Pinocytosis They are bulk transport (i.e. swallowing or drinking) of particles into a cell . They are active process involved expenditure of energy.(ATP) The particles transported into a cell can be large particles. Some of them can be seen under light microscope. Intracellular digestion is common accompanying pinocytosis and phagocytosis. Therefore they are associated with the activities of lysozomes.

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16. 1) Exocytosis involve the movement of macromolecules out of the cell by the fusion of membrane bound vesicles to the plasma membrane

17. 2 . Endocytosis [ endo = inside] movement of large materials to INSIDE of the cell by formation of vesicles. ie ; membrane may fold inward, trapping materials from the outside