Cell transportation

TWO MAJOR TYPES OF TRANSPORT THROUGH BIOLOGICAL MEMBRANE

● Transport across biological membrane

• Transport across, but not through, membrane

1. Endocytosis

1.1. Phagocytosis : solid particle, “cell eating”1.2. Pinocytosis : soluble molecules “cell drinking”1.3. Receptor-mediated endocytosis

2. Exocytosis

Transport across, but not through, membrane

= Bulk transport

1.3. Receptor-medated endocytosis

SUTHILUK PATUMRAJ, Ph.D.Department of Physiology

Faculty of Medicine, Chulalongkorn University

LDL-c

2. ExocytosisExample:

Neurotransmitters;

acetylcholine (Ach)

SUTHILUK PATUMRAJ, Ph.D.Department of Physiology

Faculty of Medicine, Chulalongkorn University

active zone

trafficking

1. SIMPLE DIFFUSION

- osmosis : solvent

- diffusion : solute

2. CARRIER MEDIATED TRANSPORT

2.1 FACILITATED TRANSPORT

2.2 ACTIVE TRANSPORT

2.2.1 PRIMARY ACTIVE TRANSPORT

2.2.2 SECONDARY ACTIVE TRANSPORT

Transport across biological membrane

Membrane Transport of Small MoleculesMembrane Transport of Small Molecules

FICK FIRST LAW OF DIFFUSION

J = - D A dC / d X

D = DIFUSSION COEFFICIENT

A = AREA

dC = CONCENTRATION GRADIENT

dx = DISTANCE

Lipid solubilitysize

viscositytemperature

SIMPLE DIFFUSION

OSMOSISAbout 300 mlosmole/L

Hemolysis crenation

IONIC CHANNEL

GATING MECHANISMS

SELECTIVITY

CARRIER MEDIATED TRANSPORT

•SUTHILUK PATUMRAJ, Ph.D.

• Department of Physiology• Faculty of Medicine, Chulalongkorn University

Competition Molecules

X + Y

[C] ECF

[C]ICF

• GLUCOSE TRANSPORTER

• AMINO ACID TRANSPORTER

FACILITATED TRANSPORT

ACTIVE TRANSPORT

PRIMARY ACTIVE TRANSPORT

Na+ - K+ ATPase

K+ - H+ ATPase

Ca2+ - ATPase

SECONDARY ACTIVE TRANSPORT

CO-TRANSPORT

COUNTER-TRANSPORT

ATP

Na+

Energy source

•SUTHILUK PATUMRAJ, Ph.D.

• Department of Physiology• Faculty of Medicine, Chulalongkorn University

““HomeostasisHomeostasis””