Ion c .ppt

ION CHANNELS

Presented By-Ashutosh Tambare

Ashwin kolhatkarJayti saparia

Kriti KatyayanRaghuramreddy

Rajan Pandey

OUTLINE• What are ion channels?• Channel structure• Types of Gating in Ion Channels• The sodium-potassium pump• Working of ion channels• Importance of ion channels

WHAT ARE ION

CHANNELS ???

They are porous transmembral proteins which help in regulating

the voltage gradient across the plasma

membrane by allowing ions to diffuse through the

pores down their electrochemical gradients.

WHY DO WE

NEED THEM???

Ions Cannot Diffuse Across the Hydrophobic

Barrier of the Lipid Bilayer.

Structure???

Types of Gating in Ion Channels

There are Four Types of Gating Controls -

1. Ligand Gating 2. Phosphorylation

The Sodium-Potassium PumpExtracellular fluid with high concentration of Na+

Cytoplasm with high concentration of K+1

Three Na+ bind to the cytoplasmic side of the protein.

2

Phosphate is transferred from ATP to the protein.

3Phosphorylation changes theshape of theprotein, movingNa+ across themembrane.

4

K+ binds to the protein, causingphosphaterelease.

5Release ofphosphatechanges theshape of theprotein, moving K+ to the cytoplasm.

Na+

ATP ADPP

Na+

P

K+

PK+

+ + + +

- - - -

Vm = Q/C

∆Vm = ∆Q/C

THE LIPID BILAYER ACTS LIKE A CAPACITOR

∆Q must change before

∆Vm can change

CHANGE IN CHARGE SEPARATION ACROSS

MEMBRANE CAPACITANCE IS REQUIRED TO CHANGE MEMBRANE

POTENTIAL

-

--

-

-

-

-

--

- -

-

-

-+

++

+

+

+

+

+

-

-

+

++

++

+

++

IMPORTANCE OF ION CHANNELS

• Mediate the generation, conduction and transmission of electrical signals in the nervous system• Control the release of

neurotransmitters and hormones• Transfer small molecules between

cells (gap junctions)

THANK YOU