Membrane Structure and Function
Sample Exam Questions

Main Sample Questions List

1.    Which of the following statements concerning the aquaporin family of membrane proteins is TRUE?
     
  A. These peripheral membrane proteins function as water selective channels.
  B. Specific mutations may result in the inactivation of the aquaporin expressed in the kidney and the subsequent development of diabetes insipidus.
  C. These proteins usually contain two transmembrane domains and must assemble as a tetramer in order to be functional.
  D. These unique proteins are found only in the plasma membrane of epithelial cells present in salivary glands.
   
    ANSWER

2.    The facilitated diffusion of glucose into a red blood cell is characterized by which of the following?
     
  A.  Unlike simple diffusion, this form of transport is stereospecific.
  B. Glucose enters the red blood cell against its concentration gradient.
  C. This process requires the simultaneous co-transport of Na+ ions down their electrochemical gradient.
  D. The KM of facilitated transport is the external concentration of glucose that results in maximal transport velocity.
   
    ANSWER

3.    Which of the following statements concerning the lipid composition of the plasma membrane is FALSE?
     
  A. Membrane phospholipids are amphipathic and contain two hydrophobic fatty acyl chains, each typically containing an even number of carbon atoms.
  B. Glycolipids represent the most abundant class of membrane lipids.
  C. Cholesterol intercalates between phospholipids and slows their lateral movement within the plasma membrane.
  D. The hydrophobic effect drives the formation of the phospholipid bilayer.
   
    ANSWER

4.    A recently discovered membrane-associated protein exhibits the following properties: molecular weight = 130,000; three separate stretches of nonpolar amino acids that form a helices; long hydrophilic extracellular domain that contains sugar residues; and a short hydrophilic intracellular domain. This protein would be most ACCURATELY described by which of the following?
     
  A. tripartite, single-pass integral membrane glycoprotein
  B. multipass integral membrane glycoprotein with one extracellular loop
  C. multipass integral membrane glycoprotein with two intracellular loops
  D. large transmembrane protein with an extracellular ligand-binding domain
    large integral membrane protein with two extracellular loops
   
    ANSWER

5.    Which of the following statements concerning the intestinal glucose-Na+ symport system is FALSE?
     
  A. The symport protein itself is a large integral membrane protein with distinct extracellular binding sites for Na+ and glucose.
  B. This symport system is an example of secondary active transport.
  C. Binding of Na+ and glucose to the symport protein induces a conformational change and creates a channel through which they can be transported into the cytosol.
  D. This symport system facilitates the diffusion of glucose down its concentration gradient and across the apical membrane of an intestinal cell.
  E. Inhibition of the Na+/K+-ATPase activity with ouabain would ultimately cause this symport system to cease functioning.
   
    ANSWER

Back to Lecture Schedule

Back to Main Menu

Return to Top