• Sample exam
    • 2. Describe in general terms the steps involved in the FRAP (fluorescence recovery after photobleaching) technique, and how a membrane lipid diffusion constant can be derived from this approach (5 pts).
    How would each of the following affect the diffusion constant for membrane lipids ? (4 pts)
    a. increased average chain length of fatty acids ______________________
    b. increased numbers of fatty acids with double bonds ________________
    3. What are two types of lipid asymmetries found in membrane bilayers (4 pts)?
    4. A protein is isolated from a cell homogenate and its amino acid sequence is determined. A highly hydrophobic domain is found within the protein sequence, consisting of 22 amino acids, mostly hydrophobic (valine, phenylalanine), but with every third amino acid hydrophilic. What might you deduce about this protein's location and subunit organization in the native state? (4 pts)
    5. Draw a hypothetical recording of single channel activity, as might be obtained by the patch-clamping method. Label Axes. What channel properties can be derived from such a recording? (6 pts).
    6. List some of the structural and functional properties of the voltage-gated K+ ion channel (4 pts).
    Generally, how are ion channels like this thought to maintain selectivity among various cations? (4 pts).
    7. List the sequence of intracellular events required for activation of the CFTR channel (4 pts).
    8. Compare the two types of glucose transporters, SGLT and GLUT, with regard to:
    a. location within cells and transport properties (4 pts)
    b. operational models of ligand transport (4 pts)
    9. Compare collagen type I and collagen type IV with regard to molecular and structural features, properties and location (use         lists or sketches) (6 pts).
    10. What is the significance of the RGD (arginine-glycine-aspartic acid) sequence. Where is it found and what is its importance? (6 pts).
    11. Describe the general structural and functional properties of integrins (4 pts)
    Give one example of inside-out integrin signaling and one example of outside-in signaling (4 pts)
    12. Match the following from the list at the right: (6 pts)
    induces expression of platelet integrins _______                                 a. syndecan
                                                                                                         b. CD-44
    membrane-associated heparin-sulfate _______ proteoglycan                 c. paxillin
                                                                                                         d thrombin                                                                type of cell-to-cell adhesion molecule _______                                  e. selectin
    13. So-called attachment-dependent cells require adhesion to the extracellular matrix (or substrate). Cells which do not correctly attach undergo a deliberate cell death called
                                                             __________________________ (2 pts)
    Explain briefly how successful attachment prevents this cell death. ( 5 pts).
    Part II. Pick two. Choose two of the following questions to answer. Provide complete information in the form of labeled sketches, diagrams or flow charts. (10 pts each).
    a. Describe several of the major proteins of RBC ghosts, including information about structure, function and overall organization.
    Explain how these proteins contribute to the normal function and physical properties of the RBC.
    b. Describe the operational model for the function of the Na+/K+ ATPase, particularly the role of ATP.


             c. List steps or sketch the processes involved in neutrophil extravasation, with emphasis on the role of various cell adhesion
         molecules.