TRANSPORT ACROSS MEMBRANES

12/24/97


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Table of Contents

TRANSPORT ACROSS MEMBRANES

HOW DO WE CHARACTERIZE TRANSPORT ACROSS MEMBRANES?

THE STEADY STATE

HOMEOSTASIS IS LIKE A STEADY STATE AWAY FROM EQUILIBRIUM

PPT Slide

THE RESTING CELL

EQUILIBRIUM RESULTS FROM ISOLATING THE SYSTEM

EQUILIBRIUM FOR A CELL MEANS DEATH

DEFINITION OF A FLOW

MEASUREMENT OF A FLOW

TWO MAJOR TYPES OF TRANSPORT

Passive Transport

Diffusion

Diffusion across a permeable membrane

Impermeable membrane

MEASUREMENT OF A FLOW

MEASUREMENT OF A PERMEABILTY

FICK’S LAW FOR DIFFUSION

OIL/WATER PARTITION: THE “KITCHEN” EXPERIMENT

PERMEABILITY AND OIL/WATER PARTITION

THE MAJOR BARRIER IN THE CELL MEMBRANE IS LIPID

PARTITION AND PERMEABILITY

PARTITION AND PERMEABILITY

PARTITION AND PERMEABILITY

DIFFUSION OCCURS IN THE MEMBRANE

Bulk Flow

BULK FLOW

POISEUILLE’S LAW FOR BULK FLOW

Current Flow

OHM’S LAW FOR CURRENT FLOW

IONS MOVE WITH THEIR HYDRATION SHELLS

MOBILITY OF IONS DEPENDS ON HYDRATED SIZE

ELECTRONEUTRAL DIFFUSSION

ELECTRONEUTRAL DIFFUSSION

ELECTRONEUTRAL DIFFUSSION

ELECTRONEUTRAL EXCHANGE

ELECTRONEUTRAL EXCHANGE

THE ORIGIN OF BIOELECTRICITY

FICK’S LAW FOR DIFFUSION

Osmosis

POISEUILLE’S LAW FOR BULK FLOW WHEN OSMOSIS IS PRESENT

A GENERALISATION FOR ALL LINEAR FLOW PROCESSES

A SUMMARY OF ALL LINEAR FLOW PROCESSES

Facilitated Diffusion

ACTIVE TRANSPORT REQUIRES AN INPUT OF ENERGY

ACTIVE TRANSPORT

PPT Slide

THE RESTING CELL

Author: Donald C. Mikulecky

Email: mikulecky@gems.vcu.edu

Home Page: http://views.vcu.edu/~mikuleck/