Mutations of Lysine to Alanine residues near the membrane water interface disrupts binding to the lipids. Which portion of the lipid does the protein bind to, the head group or the acyl chain, given the mutation?

Estimate the number of amino acid residues in each of the two helices of a segment of the alpha-keratin coiled coil that is 23 nm long.

Lipid bilayers form spontaneously in a process driven by the hydrophobic effect. Explain how the hydrophobic effect drives bilayer formation from individual lipids in an aqueous environment. Describe how the physical properties of the lipid bilayer are determined by the chemical properties of the membrane lipid components. Diagrams are encouraged for both parts of the question.

Of the following cell membrane lipids, which one prefers to reside in the inner leaflet (or inner half) of the membrane bilayer, AND has an overall neutral charge at physiological pH (7.4)? a) PE (phosphatidylethanolamine) is inner-leaflet with an overall neutral charge at pH 7.4 b) SM (sphinogomyelin) is inner-leaflet with an overall neutral charge at pH 7.4 c) PS (phosephatidylserine) is inner-leaflet with an overall neutral charge at pH 7.4 d) PC (phosphatidylcholine) is inner-leaflet with an overall neutral charge at pH 7.4