3. Solute Transport across Membranes

Transport May Be Passive or Active

Transporters and Ion Channels Share Some Structural Properties but Have Different Mechanisms

The Glucose Transporter of Erythrocytes Mediates Passive Transport

The Chloride-Bicarbonate Exchanger Catalyzes Electroneutral Cotransport of Anions across the Plasma Membrane

BOX 11-1 Defective Glucose Transport in Diabetes

Active Transport Results in Solute Movement against a Concentration or Electrochemical Gradient

P-Type ATPases Undergo Phosphorylation during Their Catalytic Cycles

V-Type and F-Type ATPases Are ATP-Driven Proton Pumps

ABC Transporters Use ATP to Drive the Active Transport of a Wide Variety of Substrates

BOX 11-2 A Defective Ion Channel in Cystic Fibrosis

Ion Gradients Provide the Energy for Secondary Active Transport

Aquaporins Form Hydrophilic Transmembrane Channels for the Passage of Water

Ion-Selective Channels Allow Rapid Movement of Ions across Membranes

The Structure of a K+ Channel Reveals the Basis for Its Specificity