This document discusses different modes of transport across cell membranes, including passive transport, active transport, and fluid transport. It specifically focuses on phagocytosis, which involves the engulfing and destruction of pathogens by immune cells. There are two main classes of phagocytic cells - polymorphonuclear granulocytes and macrophages. The key steps of phagocytosis are the capture of particles by membrane extensions, engulfment in a phagosome, and destruction of the pathogen through killing mechanisms inside the phagosome and lysosome.

1. © SVDcreations

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

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

7. 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

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

9. STEPS

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

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

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

15. 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.

16. 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.

17. 839 Shivani
840 Vishwanath
841 Divesh

18. THANK YOU

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

20. 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