Fundamentals of Biological Sciences
Lecture5
Dr. Açelya Yılmazer
THE LIPID BILAYER
• Membrane Lipids Form Bilayers in Water
• The Lipid Bilayer Is a Flexible Two-dimensional Fluid
• The Fluidity of a Lipid Bilayer Depends on Its Composition
• Membrane Assembly Begins in the ER
• Certain Phospholipids Are Confined to One Side of the Membrane
THE LIPID BILAYER
• Membrane Lipids Form Bilayers in Water
• The Lipid Bilayer Is a Flexible Two-dimensional Fluid
• The Fluidity of a Lipid Bilayer Depends on Its Composition
• Membrane Assembly Begins in the ER
• Certain Phospholipids Are Confined to One Side of the Membrane
THE LIPID BILAYER
• Membrane Lipids Form Bilayers in Water
• The Lipid Bilayer Is a Flexible Two-dimensional Fluid
• The Fluidity of a Lipid Bilayer Depends on Its Composition
• Membrane Assembly Begins in the ER
• Certain Phospholipids Are Confined to One Side of the Membrane
THE LIPID BILAYER
• Membrane Lipids Form Bilayers in Water
• The Lipid Bilayer Is a Flexible Two-dimensional Fluid
• The Fluidity of a Lipid Bilayer Depends on Its Composition
• Membrane Assembly Begins in the ER
• Certain Phospholipids Are Confined to One Side of the Membrane
THE LIPID BILAYER
• Membrane Lipids Form Bilayers in Water
• The Lipid Bilayer Is a Flexible Two-dimensional Fluid
• The Fluidity of a Lipid Bilayer Depends on Its Composition
• Membrane Assembly Begins in the ER
• Certain Phospholipids Are Confined to One Side of the Membrane
MEMBRANE PROTEINS
• Membrane Proteins Associate with the Lipid Bilayer in Different Ways
PRINCIPLES OF TRANSMEMBRANE TRANSPORT
• Lipid Bilayers Are Impermeable to Ions and Most Uncharged Polar Molecules
• The Ion Concentrations Inside a Cell Are Very Different from Those Outside
• Differences in the Concentration of Inorganic Ions Across a Cell Membrane Create a
Membrane Potential
• Cells Contain Two Classes of Membrane
Transport Proteins: Transporters and Channels
PRINCIPLES OF TRANSMEMBRANE TRANSPORT
• Lipid Bilayers Are Impermeable to Ions and Most Uncharged Polar Molecules
• The Ion Concentrations Inside a Cell Are Very Different from Those Outside
• Differences in the Concentration of Inorganic Ions Across a Cell Membrane Create a
Membrane Potential
• Cells Contain Two Classes of Membrane
Transport Proteins: Transporters and Channels
PRINCIPLES OF TRANSMEMBRANE TRANSPORT
• Lipid Bilayers Are Impermeable to Ions and Most Uncharged Polar Molecules
• The Ion Concentrations Inside a Cell Are Very Different from Those Outside
• Differences in the Concentration of Inorganic Ions Across a Cell Membrane Create a
Membrane Potential
• Cells Contain Two Classes of Membrane
Transport Proteins: Transporters and Channels
PRINCIPLES OF TRANSMEMBRANE TRANSPORT
• Lipid Bilayers Are Impermeable to Ions and Most Uncharged Polar Molecules
• The Ion Concentrations Inside a Cell Are Very Different from Those Outside
• Differences in the Concentration of Inorganic Ions Across a Cell Membrane Create a
Membrane Potential
• Cells Contain Two Classes of Membrane
Transport Proteins: Transporters and Channels
PRINCIPLES OF TRANSMEMBRANE TRANSPORT
• Solutes Cross Membranes by Either Passive or Active Transport
• Both the Concentration Gradient and
Membrane Potential Influence the Passive Transport of Charged Solutes
• Water Moves Passively Across Cell Membranes Down Its Concentration Gradient—a Process Called Osmosis
PRINCIPLES OF TRANSMEMBRANE TRANSPORT
• Solutes Cross Membranes by Either Passive or Active Transport
• Both the Concentration Gradient and
Membrane Potential Influence the Passive Transport of Charged Solutes
• Water Moves Passively Across Cell Membranes Down Its Concentration Gradient—a Process Called Osmosis
PRINCIPLES OF TRANSMEMBRANE TRANSPORT
• Solutes Cross Membranes by Either Passive or Active Transport
• Both the Concentration Gradient and
Membrane Potential Influence the Passive Transport of Charged Solutes
• Water Moves Passively Across Cell Membranes Down Its Concentration Gradient—a Process Called Osmosis
