Membrane Structure
Dec 22, 2015
Membrane Structure
Membrane StructureReview: Phospholipid structure and properties
*amphipathic
Membrane Models:
1935 Today
Cell biology at work: membranes “uncovered”
*Membranes are fluid
Membranes are fluid
*Some functions of membrane proteins:
Transport
Enzymatic activity
Signal transduction
Intercellular junction
Cell recognition
Anchors
Membrane Transport
*Channel protein *Carrier protein
Traffic across membranes
*Passive transport
*Active transport
Passive transport
*Selective permeability
*Diffusion
Osmosis is the passive transport of waterWhen comparing two solutions:
*hypertonic
*hypotonic
*isotonic
Passive transportFacilitated diffusion
Channel proteins and carrier proteins
*Each cell membrane has characteristic set of carrier
proteins
*Active transport
Example: sodium-potassium pump
Electrogenic pump:
*Some ion pumps generate voltage across membranes
*Voltage*Membrane potential