Biochemistry II Final Review

64 Questions | Total Attempts: 118

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Biochemistry Quizzes & Trivia

Questions and Answers
  • 1. 
    In biological membranes the PREDOMINANT interaction between the proteins and phospholipids is probably
    • A. 

      Hydrogen bonding

    • B. 

      Hydrophobic interaction

    • C. 

      Ionic interactions

    • D. 

      Covalent linkages

  • 2. 
    Cholesterol, phosphatidylserine, and palmitate have in common:
    • A. 

      A phosphate group

    • B. 

      A hydrophobic unit

    • C. 

      An acyl chain

    • D. 

      A carboxylate group

    • E. 

      A free hydroxyl group

  • 3. 
    Phosphatides may contain glycerol in ester linkages to two fatty acids, and in phosphodiester linkage with which of the following alcohols?
    • A. 

      Choline, serine, ethanolamine

    • B. 

      Choline, sphingosine, serine

    • C. 

      Serine, cholesterol, choline

    • D. 

      All of the above

    • E. 

      None of the above

  • 4. 
    Integral membrane proteins that exhibit an intrinsic activity of hydrolyzing ATP to ADP and Pi most likely participate in
    • A. 

      Binding polypeptide hormones

    • B. 

      Generation intracellular messengers during signal transduction

    • C. 

      Initiating one or more steps in blood coagulation

    • D. 

      Moving cations against their concentration gradient

    • E. 

      Targeting proteins to different organelles

  • 5. 
    Which of the following is most likely to cross a membrane by a non-mediated diffusion process?
    • A. 

      Glucose

    • B. 

      Carbon dioxide

    • C. 

      Sodium ions out of cells

    • D. 

      ADP

  • 6. 
    A structural feature common to all membrane forming lipids is:
    • A. 

      Charged groups

    • B. 

      Fatty acyl groups

    • C. 

      Hydroxyl groups

    • D. 

      Amphipathic character

    • E. 

      Detergent property

  • 7. 
    A typical transmembrane domain in a protein is
    • A. 

      An alpha helix containing mostly aromatic amino acids

    • B. 

      An alpha helix containing a mixture of nonpolar amino acids

    • C. 

      A beta sheet containing alternating polar and nonpolar amino acids

    • D. 

      A beta sheet containing mostly nonpolar amino acids

  • 8. 
    Differences in bilayer fluidity among human cell membranes are due to
    • A. 

      Changes in membrane potential resulting from ATP-driven ion pumps

    • B. 

      Fluctuations in body temperature

    • C. 

      Interactions between phosphatidylethanolamine

    • D. 

      The level of monoacylglycerol

    • E. 

      The ratio of cholesterol to phospholipids

  • 9. 
    Each of the following lipid types is a membrane constituent EXCEPT which one?
    • A. 

      Sphingolipids

    • B. 

      Phospholipids

    • C. 

      Gangliosides

    • D. 

      Triglycerides

    • E. 

      Cholesterol

  • 10. 
    Phospholipids have the property of detergency. This is due primarily to
    • A. 

      Polar head groups

    • B. 

      A hydrocarbon tail

    • C. 

      An amphipathic nature

    • D. 

      Solubility

  • 11. 
    The organization of glycerophospholipid phosphatidylserine in an aqueous environment is:
    • A. 

      Monomer with serine and fatty acyl residues exposed to water

    • B. 

      Micelle with the serine residues exposed to water

    • C. 

      Micelle with the serine residues sequestered from water

    • D. 

      Bilayer with the fatty acyl residues exposed to water

    • E. 

      Bilayer with the fatty acyl residues sequestered from water

  • 12. 
    At physiological pH, phosphatidylinositol would exist mainly as a species with a net charge of:
    • A. 

      +1

    • B. 

      –2

    • C. 

      –1

    • D. 

      +2

    • E. 

      0

  • 13. 
    Proteins in membranes
    • A. 

      Are located only at the external surface of the membrane

    • B. 

      Have carboxy termini is usually oriented toward the exterior part of the cell

    • C. 

      Consist of a small number of low molecule weight proteins

    • D. 

      Are located both on the surface and in the interior of the membrane

    • E. 

      Are located only in the internal portion of the membrane

  • 14. 
    Phospholipids and glycolipids in membranes are organized primarily as:
    • A. 

      A micelle

    • B. 

      A monomolecule sheet

    • C. 

      A trimer

    • D. 

      A bimolecular layer

    • E. 

      None of the above

  • 15. 
    Which of the following pairs of compounds are components of a phospholipid?
    • A. 

      CDP and inositol

    • B. 

      Monoglyceride and choline

    • C. 

      Phosphatidic acid and CDP

    • D. 

      Phosphatidic acid and ethanolamine

    • E. 

      Sphingosine and lecithin

  • 16. 
    All of the following statements about internal membrane proteins are true EXCEPT 
    • A. 

      They are associated with lipid in the membrane

    • B. 

      They can be transmembranous

    • C. 

      They are amphipathic

    • D. 

      They are symmetrically distributed within the membrane

    • E. 

      They are only removed from the membrane by drastic treatments

  • 17. 
    Typical components of a plasma membrane include all of the following EXCEPT
    • A. 

      Cholesterol

    • B. 

      Sphingomyelin

    • C. 

      Proteins

    • D. 

      Triglycerides

    • E. 

      Phospholipids

  • 18. 
    Which one of the following membranes contains the highest percentage of lipid?
    • A. 

      Endoplasmic reticulum

    • B. 

      Erythrocyte plasma membrane

    • C. 

      Myelin sheath

    • D. 

      Inner mitochondrial membrane

    • E. 

      Outer mitochondrial membrane

  • 19. 
    Optimal hydrophobic interactions between the interior of a lipid bilayer and a membrane protein would be achieved with which of the following groups of amino acids?
    • A. 

      Ala, Arg, Asp

    • B. 

      Cys, His, Pro

    • C. 

      Gln, Glu, Gly

    • D. 

      Ile, Met, Trp

    • E. 

      Ser, Thr, Tyr

  • 20. 
    Membrane fluidity
    • A. 

      Increases as the percent of unsaturated fatty acids increases

    • B. 

      Increases as the percent of unsaturated fatty acids decreases

    • C. 

      Increases as the length of the fatty acid side chains increases

    • D. 

      Is independent of the name of fatty acids

    • E. 

      Increases as the percent of saturated fatty acids increases

  • 21. 
    The structure of a biological membrane is best described as
    • A. 

      A continuous bilayer of lipids coated with proteins on either side

    • B. 

      A fluid mosaic of proteins interspersed in a lipid bilayer

    • C. 

      A phospholipid bilayer with interspersed proteins, held together by covalent and H-bonds

    • D. 

      A phospholipids bilayer with the hydrophilic groups turned inward, hydrophobic groups outward

    • E. 

      An internal layer of proteins surrounded by a sheet of lipds

  • 22. 
    Provides structural rigidity to the plasma membrane:
    • A. 

      Cholesterol

    • B. 

      Palmitate

    • C. 

      Arachidonate

    • D. 

      Diacylglycerol

    • E. 

      Oleate

  • 23. 
    Lipid bilayers
    • A. 

      Form spontaneously by the cooperative assembly of amphipathic molecules in water

    • B. 

      Form from phosphatidylcholine in an organic solvent such as chloroform

    • C. 

      Have the thickness of one molecule of phosphoglyceride or sphingolipid

    • D. 

      Are more permeable to small ions such as Na+ than to larger molecules such as glucose

    • E. 

      Are about 2A thick

  • 24. 
    Which of the following compounds could easily be converted into lipid bilayer vesicles?
    • A. 

      Bile salts

    • B. 

      Cholesterol

    • C. 

      Diacyl glycerol

    • D. 

      Lecithin (phosphatidylcholine)

    • E. 

      Stearate

  • 25. 
    As alpha-helix conformation is favored in the transmembrane domain of a membrane protein because:
    • A. 

      Intermolecular H bonding can occur stabilizing the alpha helix

    • B. 

      Within the core of the lipid bilayer, there are no other molecules which can form H-bonds and thus compete with the intramolecular H-bonds of the transmembrane peptide domain

    • C. 

      Both

    • D. 

      Neither

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