Lecture 4 BIO 344

Chapter 10 and 11

Chapter 11

Membrane Transport of Small Molecules and the Electrical

Properties of Membranes

Molecule movement across lipid bilayer without proteins

Permeability across lipid bilayer

Carrier Proteins

Channel Proteins

Passive vs. Active Transport

Three Ways of Driving Active Transport

Electrochemical gradient vs. membrane potential

Can work additively or against each other

Three Ways of Driving Active Transport

Conformational Change in Carrier Protein mediates passive transport

Three Types of Carrier Mediated Transport

DVD Clip 43

Mechanism of Na+ - glucosecarrier

Binding of Na+ and glucose is cooperative

DVD Clip 44

Microvilli in the small intestine

Transcellular transport of glucose

The Na+ - K+ pump is an ATPase

DVD clip 42

Response of red blood cells to changes in osmolarity of extra cellular fluids

Distribution of phospholipids and glycolipids in the lipid bilayer of human red blood cells

Few Ions are required to cause a large change in membrane potential

Electrochemical gradient vs. membrane potential

Can work additively or against each other

Selectivity of a K+ channel

DVD Clip 45

Ion Channels fluctuate between closed and open conformations

Gating of K+ channel

Gating of Ion Channels

A Typical Vertebrate Neuron

Ball and Chain Model of Rapid inactivation of ion channel

Propagation of Action Potential

Changes in Na+ channels and the action potential

Changes in Na+ channels and the action potential