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Home Biochemistry Protein Stability Comments

  • Question
  • Unpaired H-bond donors and acceptors are found in the hydrophobic core of a protein


  • Options
  • A. only at the ends of a-helices
  • B. only at the turns connecting p-strands
  • C. only on Pro residues
  • D. rarely

  • Correct Answer
  • rarely 


  • Protein Stability problems


    Search Results


    • 1. Buried hydrophobic side chains in a globular protein fit into a hole formed by the side chains of

    • Options
    • A. 1-3 other amino acids
    • B. 5-7 other amino acids
    • C. 9-12 other amino acids
    • D. 13-15 other amino acids
    • Discuss
    • 2. The correlation between free energy ?G transfer between the aqueous/organic phases and the surface area of amino acid residues

    • Options
    • A. reflects the reduction in solvent-accessible area during protein folding
    • B. is only meaningful for the polar amino acids
    • C. ignores the important contribution of the peptide bond
    • D. is similar to effects seen with SDS denaturation
    • Discuss
    • 3. For the unfolding reaction of Protein G, ∆H° =210.6 kJ/mol, this means that

    • Options
    • A. unfolding is favored enthalpically
    • B. folding is favored enthalpically
    • C. the entropy is positive at all temperatures
    • D. the entropy is negative at all temperatures
    • Discuss
    • 4. Which of the three subunits of the G proteins binds GDP and GTP?

    • Options
    • A. Alpha
    • B. Beta
    • C. Gamma
    • D. Delta
    • Discuss
    • 5. The heme is held in place by a bond between

    • Options
    • A. the Fe2+ and cysteine
    • B. the Fe3+ and histidine
    • C. the Fe3+ and cysteine
    • D. the Fe2+ and histidine
    • Discuss
    • 6. Since ?G° = -RTlnK

    • Options
    • A. a 10-fold increase in K decreases ?G° by about 10-fold
    • B. a 10-fold decrease in K decreases ?G° by about 2.3*RT
    • C. a 10-fold increase in K decreases ?G° by about 2.3*RT
    • D. a 10-fold decrease in K increases ?G° by about 10-fold
    • Discuss
    • 7. At the midpoint of a temperature transition curve,

    • Options
    • A. half of the protein is denatured
    • B. Keq = 1.0 and ?G = 0
    • C. [Native] = [Unfolded]
    • D. All of these
    • Discuss
    • 8. Which of the following is the most correct?

    • Options
    • A. Charged amino acids are never buried in the interior of a protein
    • B. Charged amino acids are seldom buried in the interior of a protein
    • C. All hydrophobic amino acids are buried when a protein folds
    • D. Tyrosine is only found in the interior of proteins
    • Discuss
    • 9. Which of the following forces is the most unfavorable for protein folding?

    • Options
    • A. Conformational entropy
    • B. Hydrophobic interactions
    • C. Vander Waals interactions
    • D. Electrostatic interactions
    • Discuss
    • 10. Attractive Vander Waals forces occur between

    • Options
    • A. apolar molecules in the liquid state
    • B. any pair of nearby atoms
    • C. polar molecules in the solid state
    • D. only if other forces are less favorable
    • Discuss


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