You are using PC(16:0, 16:0), PC (16:0, 18:1∆9), Sphingomyelin (18:0), and cholesterol to create lipid bilayers in aqueous solution. Which lipid composition would create the most disordered bilayer? Which lipid composition would create the most ordered bilayer? Design an experiment(s) to test your predictions and explain what you would observe in your experiments and why.

Which one of the following statements about lipids and biological membranes is incorrect?

A) Increased temperature can change the membrane from gel phase to fluid phase.

B) Membrane fluidity is affected by lipid composition but not by temperature.

C) Phospholipid bilayers are fluid.

D) For lipid movement, flex is faster than lateral shift.

E) Ions are not allowed to freely traverse a lipid bilayer.

Lipid rafts are rich in sphingolipids and cholesterol, and it is thought that cholesterol plays a central role in raft formation since lipid rafts apparently do not form in its absence. Why do your suppose that cholesterol is essential for formation of lipid rafts? (Hint: sphingolipids other than sphingomyelin have large head groups composed of several linked sugar molecules and are found in lipid rafts).

Which intermolecular porcess primarly drives the formation of a bilayer when phospholipids are added to water? Which intermolecular porcess primarly drives the formation of a bilayer when phospholipids are added to water?

A-Lipids cause water to arrange in an ordered, unfavorable cage-like structure.

B-Forcing lipids into a bilayer reduces this effect.

C-The ordered arrangement of a bilayer is more favorable than the disordered state of individual free-floating phospholipids.

D-A bilayer arrangement maximizes the strength of hydrophobic interactions among phospholipids.

E-Phospholipids self-assemble inot a bilayer due to the strong affinity they have for each other.