Ion transport through cell membranes occurs through passive and active transport mechanisms. Passive transport includes simple diffusion, facilitated diffusion, and osmosis. Simple diffusion allows small, nonpolar molecules to freely pass through the phospholipid bilayer. Facilitated diffusion uses channel and carrier proteins to transport ions and larger molecules down their concentration gradients without expending energy. Osmosis allows for the diffusion of water through semipermeable membranes. Active transport moves solutes against their concentration gradients and requires energy in the form of ATP hydrolysis. Primary active transport uses ATP and carrier proteins like Na+/K+ ATPase to pump ions. Secondary active transport couples the uphill transport of one solute to the downhill flow of another.

1. ION TRANSPORT THROUGH CELL
MEMBRANE
By-
Manish Sahu
M.Sc. Chemistry (Final)
Sp.- Physical Chemistry

2. CONTENTS
1) Introduction
2) History
3) Definition
4) Ion transport
5) Permeability of lipid
6) Permeability of protein
7) Types
8) Function
9) Conclusion
10) Reference

3. Introduction :-
 Cell is the structural function and biological unit of all
know living organism. Cell is the smallest unit of life .
 All the cell are surrounded by a thin layer of membrane
which is known as cell membrane .

4. History :-
Definition :-
 Naegeli and Cramer in 1855 the
structure seen under the light
micros in the cell membrane.
 Cell membrane is the fluid
layer around the cell of living
thing it is some time are
called plasma membrane.
 Membrane define the
external boundaries of the
cell.

5.  Only small unchanged molecule can defussed freely
thought phospho lipid bilayer.
 Some small non polar molecule such as o2,Co2 are
soluble in lipid bi-layer there fore can readily small
unchanged polar molecule.
 Ion transport
Permeability of lipid Bilayer

6.  Channel protein
 Channel protein are ion selective.
 They contain a pore in which solute pass at high flux
when the channel is open.
 They transport solutes down their concentration
gradien.
 Channel mediated transport is always passive .
 Permeability of protein

7. Carrier protein
 Carrier mediated transport maybe active or passive.
 Carrier proteins can be uniporters or co-transporter.
Uniport:-Transportation of single solute from one side of
membrane to other side .
Symport:-Transportation of two different solutes from one
side to another side .
Antiport:- Transfer of both different solutes in opposite
direction .

9. Types
Active transport
 In this type of transport nergy is derived directly from
breakdown of ARP.
 ATP and energy dependent
 The fast process
 Lower concentrations to higher concentrations
 Affected by low temperature to higher temperature
 Primary Active transport:-

10.  Transport of Na+ and K+ by carrier protein ,Na+,K+ ATP
pase is the most common example of primary active
transport.
 Virtually every animal cell maintains lower Na+
concentration and high K+ concentration than they found
in its surrounding.
 It is either symport are antiport

11. Secondary active transport
 It curs when uphill transport of one solute is coupled .with
the exergonic flow of a different solutes .
 A common example of secondary active transport is the
symport of Na+ and glucose ,whith allows Na+ and
glucose to enter the cell.

12. Passive transport:-
 Without ATPand energy.
 Slower or compare to active transport
 High concentration to low concentration.
 Not affected by low temperatur.
 Simple diffusion:-
 Cell membrane are composed of phospholipid bilayer
with interspersed protein.
 These proteins help to move larger molecule and ions
across the membrane.

13. Facilitated Diffusion and ion channels:-
Also called carrier mediated osmosis in the moment of
molecules high concentration to low concentration.
 Larger molecules and ions cannot cross the membrane by
simple diffusion.

14.  Some membrane proteins called ion channels provide a
pore for a specific type of ion to pass from one side of the
cell membrane to the other .
 This passive transport witch requires no expenditure of
energy.
 Is an example of facilitated diffusion.
Facilitated Diffusion and transport proteins.

15. Osmosis diffusion
 Water moves across a semipermeable membrane from an
area of high water concentration to an area of low water
concentration.

16. Endocytosis
Endocytosis is the ingestion of plasma membrane ingestion of
food particles or large particles of foreign substances.
Exocytosis
Exocytosis is the method by which the objects inside the cell
are taken out by the action of secretary and excretory
substances.

17. Function
 Help in electrocytosis Transport and selective permeability
 Forming cell boundary
 Protecting cell protoplasm

18. Reference :-
 Biophysical chemistry- by " J.N. Gurtu and Gurtu "
 Biophysical chemistry- by " C.B. power and G.R. chatwar"