Concept #1: Physical Properties of Biological Membranes
Concept #2: Enzymes Catalyzing Transverse Diffusion
Practice: The mobility of lipids in membranes is best described by:
a) Slow lateral diffusion and slow transverse diffusion.
b) Fast lateral diffusion and slow transverse diffusion.
c) Fast transverse diffusion and slow lateral diffusion.
d) Fast lateral diffusion and fast transverse diffusion
Concept #3: Transition Temperature of Lipid Bilayers
Practice: The fluidity of a bilayer is generally increased by:
a) The binding of water to the fatty acyl side chains.
b) An increase in fatty acid chain length.
c) An increase in the number of double bonds in the fatty acid hydrocarbon chains.
d) A decrease in temperature.
Practice: The transition temperature, Tm, for a sample cell's membrane was found to be much higher than a reference cell's membrane. What can be said about the membrane contents based on this experiment?
a) The sample cell is likely to have a higher cis-fatty acid content than the reference cell.
b) The sample cell is likely to have lower saturated fat content than the reference cell.
c) The sample cell is likely to have more polyunsaturated fatty acids than the reference cell.
d) The sample cell is likely to have higher saturated fat content than the reference cell.
Practice: Which of the following would increase the transition temperature of a membrane?
a) A decrease in the fatty acid tail length.
b) An increase in the number of double bonds in the fatty acid chains.
c) Loose packing of fatty acid tails.
d) Free fatty acids in the environment.
e) None of the above would increase the transition temperature.
