1. HW 1-6 MEMBRANES – PHOSPHOLIPID BILAYER
Link to fluid mosaic video

2. Link to triglyercide animation
Fig. 5-11
Fatty acid
(palmitic acid)
Glycerol
(a) Dehydration reaction in the synthesis of a fat
Link to triglyercide animation
Ester linkage
Figure 5.11 The synthesis and structure of a fat, or triacylglycerol
(b) Fat molecule (triacylglycerol)

3. PHOSPHOLIPIDS ARE THE MAJOR STRUCTURAL COMPONENTS OF MEMBRANES
ON TEST; BE ABLE TO DRAW BILAYER USING SHORTHAND NOTATION
Link to phospholid video

4. ASSOCIATION OF HYDROPHOBIC TAILS DRIVES THE FORMATION OF THE BILAYER
Fig. 7-2
ASSOCIATION OF HYDROPHOBIC TAILS DRIVES THE FORMATION OF THE BILAYER
BiopticVideo Link
WATER
Hydrophilic
head
Hydrophobic
tail
WATER

5. Phospholipid Bilayer behaves as a “crystalline liquid” ; structure has relatively high organization but individual molecules can slide past each other
Lateral movement
(107 times per second)
Flip-flop
( once per month)

6. Viscosity (Fluidity), how easily molecules can move laterally within membrane is determined by the type of hydrocarbon tail (unsaturated or saturated) and the concentration of cholesterol embedded in the membrane.
Link to membrane animation
Fluid
Viscous
Saturated hydro-
carbon tails
Unsaturated hydrocarbon
tails with kinks
Tighter packing = stronger LDF, thicker viscosity

7. Link to diffusion Sumanas
Hydrophobic Interior and Electrically Charge Hydrophilic Heads of Phospholipid Bilayer repels Ions and Large Polar Molecules; Small polar molecules may pass slowly through the membrane; Small hydrophobic molecules pass through the membrane easily
Link to diffusion Sumanas
Link to selectively permeable

8. Passage of ions, large polar molecules and even water is carefully regulated by use of transmembrane proteins.
Ion Channels selectively allows K+, Na+ or Ca+2 ions to flow across membrane in response to a signal
Aquaporin – regulates passage of water through membrane
Animation Active Transport

9. Passage of ions, large polar molecules and even water is carefully regulated by use of transmembrane proteins.
Glucose capture by transporter protein
Link to McGraw-Hill Membrane and Transport

10. Extension: Liposomes are used to deliver hydrophilic drugs though bilayers
Big Problem in Medicine: How to deliver drugs to the correct location in the cell
Link to liposome

11. ON TEST Glycoproteins – important in cell-cell recognition
Cholesterol – stabilize membrane structures
Peripheral Proteins – attached to surface of membrane
Integral Proteins – embedded within membrane; usually transmembrane (pass through membrane)

12. 6 ROLES OF TRANSMEMBRANE PROTEINS
FRONTIERS OF CELL BIOLOGY
HOW DO CELLS IN A MULTICELLUAR ORGANISM ATTACH TOGETHER?
HOW DO THEY BUILD A TISSUE?
HOW DO THEY COMMUNICATE AND COORDINATE ACTIVITIES?