Essential Biochemistry, 3rd Edition Test Bank

Package Title: Pratt &Cornely Test Bank Course Title: Pratt &Cornely Chapter Number: 2 Question type: Multiple Choice 1) In a water molecule, hydrogens are partially _____; oxygens are partially _____. A) negative; negative B)negative; positive C)positive; positive D) positive; negative E)none of the above Answer: D Difficulty: Easy Section Reference: 2-1 Learning Objective: Explain water’s properties in terms of its ability to form hydrogen bonds 2) At any given moment, a single water molecule participates in _____ strong hydrogen bond(s). The role played by the water molecule is best characterized as _____. A)two ; one H-bond donor, one H-bond acceptor B)two ; two H-bond donor C)two ; two H-bond acceptor D)one; H-bond donor E)one; H-bond acceptor Answer: A Difficulty: Medium Section Reference: 2-1 Learning Objective: Explain water’s properties in terms of its ability to form hydrogen bonds 3) Which of the following is a physical property of water that results from hydrogen bonding? A)high boiling point relative to molecular weight B)a solid state that is less dense than the liquid state C)high surface tension D)ability to solubilize polar molecules E) all of the above Answer: E Difficulty: Medium Section Reference: 2-1 Learning Objective: Explain water’s properties in terms of its ability to form hydrogen bonds 4) In a hydrogen bond between a water molecule and another biomolecule, _____. A) a hydrogen ion on the water molecule forms an ionic bond with a hydride ion on the other molecule B) the hydrogen bond will typically form between a hydrogen atom and either a nitrogen, sulfur, or oxygen atom C) the partial charge on a hydrogen of the water interacts with the partial charge on a hydrogen of the other molecule D) a hydrogen on the water molecule forms a covalent bond to an oxygen or nitrogen atom on the other molecule E) the hydrogen atom is located between an oxygen atom of the water and a carbon atom of the other molecule Answer: B Difficulty: Medium Section Reference:2-1 Learning Objective: Explain water’s properties in terms of its ability to form hydrogen bonds 5) The strongest non-covalent interactions are _____. A) van der Waals interactions B) London dispersion forces C)hydrogen bonds D) dipole-dipole interactions E)ionic interactions Answer: E Difficulty: Easy Section Reference: 2-1 Learning Objective: Explain water’s properties in terms of its ability to form hydrogen bonds 6)Hydrogen bonds are approximately _____% of the bond strength of covalent C-C or C-H bonds. A) 1 B) 5 C) 20 D) 50 E) 95 Answer: B Difficulty: Easy Section Reference:2-1 Learning Objective: Explain water’s properties in terms of its ability to form hydrogen bonds 7) Due to the formation of hydrogen bonds, _____ is highly soluble in water. A)carbon dioxide B)sodium chloride C)methanol D)octane E)cholesterol Answer: C Difficulty: Medium Section Reference: 2-1 Learning Objective: Explain water’s properties in terms of its ability to form hydrogen bonds 8) Which of the following explains the interactions that occur between the atoms of water molecules and the ions that form when sodium chloride dissolves in water? A)hydrogens interact with the sodium ion, oxygens interact with the chloride ion B)hydrogens interact with the chloride ion, oxygens interact with the sodium ion C)hydrogens interact with the sodium ion and the chloride ion D)oxygens interact with the sodium ion and the chloride ion E)none of the above Answer: B Difficulty: Medium Section Reference: 2-1 Learning Objective: Explain water’s properties in terms of its ability to form hydrogen bonds 9) Which of the following functional groups has two hydrogen bond donors and one hydrogen bond acceptor? A)alcohol B)ester C)thiol D)amine E)amide Answer: D Difficulty: Hard Section Reference: 2-1 Learning Objective: Explain water’s properties in terms of its ability to form hydrogen bonds 10) Hydrogen bonds within liquid water are _________. A)attractions between the protons of the oxygen nuclei B) ion-induced dipole interactions C) dipole-dipole interactions D)attractions between two oxygen atoms E)attractions between the H+ and –OH ions of the liquid Answer: C Difficulty: Medium Section Reference: 2-1 Learning Objective: Explain water’s properties in terms of its ability to form hydrogen bonds 11) When a non-polar substance is added to water, how do the molecules of water behave? A)the regular hydrogen bond pattern is disrupted resulting in a decrease of entropy B)the regular hydrogen bond pattern is disrupted resulting in an increase of entropy C)the regular hydrogen bond pattern is disrupted resulting in a decrease of enthalpy D)the regular hydrogen bond pattern is disrupted resulting in an increase of enthalpy E)none of the above Answer: A Difficulty: Medium Section Reference: 2-2 Learning Objective: Relate the solubility of substances to the hydrophobic effect 12) What term is used to describe the exclusion of nonpolar substances from an aqueous solution? A)nonpolar effect B)lipid effect C)hydrophobic effect D)oil droplet effect E)amphiphilic effect Answer: C Difficulty: Easy Section Reference: 2-2 Learning Objective: Relate the solubility of substances to the hydrophobic effect 13) Which of the following is an example of the hydrophobic effect? A)the lipid membrane of cells and organelles B)protein folding that places hydrophobic amino acids in the interior of the protein C)the separation of salad dressing D)oil sheens seen on the ocean following an oil spill E) all of the above Answer: E Difficulty: Easy Section Reference: 2-2 Learning Objective: Relate the solubility of substances to the hydrophobic effect 14) Which of the following explains the attractive forces between hydrophobic molecules in an aqueous solution? A)in an aqueous environment, London dispersion forces between hydrophobic molecules become stronger B)in an aqueous environment, London dispersion forces between hydrophobic molecules and water become stronger C)since nonpolar molecules do not form hydrogen bonds with hydrogen bonds with water, they can form hydrogen bonds with other nonpolar molecules D)there is no increase in attractive forces between nonpolar molecules in an aqueous environment E)none of the above Answer: D Difficulty: Hard Section Reference: 2-2 Learning Objective: Relate the solubility of substances to the hydrophobic effect 15) Considering the energetics of transferring nonpolar molecules from water to a nonpolar solvent, the factor TS is generally _____, causing G to be _____. A) positive; negative B)negative; negative C)positive; positive D)positive; positive E)negligible; either positive or negative Answer: A Difficulty: Hard Section Reference: 2-2 Learning Objective: Relate the solubility of substances to the hydrophobic effect 16) A molecule that has both a polar and nonpolar region is called _____________. A)micelleic B)amphiphilic C)endergonic D)a membrane E)none of the above Answer: B Difficulty: Easy Section Reference: 2-2 Learning Objective: Relate the solubility of substances to the hydrophobic effect 17) Which of the following is an example of an amphipathic molecule? A)adenine, a base found in nucleic acids B)glucose, a monosaccharide C)serine, an amino acid D)palmitic acid, a fatty acid E)none of the above Answer: D Difficulty: Medium Section Reference: 2-2 Learning Objective: Relate the solubility of substances to the hydrophobic effect 18) In aqueous solution, globules of up to several thousand amphiphilic molecules arranged with the hydrophilic groups on the surface and the hydrophobic groups buried in the center are called_____. A)micelles B)vacuoles C)liposomes D)bilayers E)none of the above Answer: A Difficulty: Easy Section Reference: 2-2 Learning Objective: Relate the solubility of substances to the hydrophobic effect 19) Fatty acid anions most commonly assemble into _____ in aqueous solution. A)lipid bilayers B) solvent-filled vesicles C)micelles D)liposomes E)none of the above Answer: C Difficulty: Easy Section Reference: 2-2 Learning Objective: Relate the solubility of substances to the hydrophobic effect 20) Which of the following molecules would be prevented from readily crossing a lipid bilayer? A)glucose B)sodium ions C)potassium ions D)water E) all of the above Answer: E Difficulty: Medium Section Reference: 2-2 Learning Objective: Relate the solubility of substances to the hydrophobic effect 21) Which of the following is true regarding hydrophobic interactions between nonpolar molecules or groups? A)they result from the tendency to maximize water’s contact with nonpolar molecules B)they require the presence of surrounding water molecules C)they are the result of strong attractions between nonpolar regions D)they are the result of strong repulsion between water and nonpolar regions E)they depend on strong permanent dipoles in the nonpolar molecules Answer: B Difficulty: Medium Section Reference: 2-2 Learning Objective: Relate the solubility of substances to the hydrophobic effect 22) In an aqueous solution, if the [OH-] is 3.010-5 M, what is the [H+]? A) 7.010-9 B) 7.010-2 C) 3.310-3 D) 3.310-10 E)none of the above Answer: D Difficulty: Medium Section Reference: 2-3 Learning Objective:Calculate the effect of acids and bases on a solution’s pH 23) What is the [H+] of an aqueous solution with a pH of 6.2? A) 6.210-6 B) 1.610-8 C) 6.310-7 D) 3. 310-5 E)none of the above Answer: C Difficulty: Medium Section Reference: 2-3 Learning Objective:Calculate the effect of acids and bases on a solution’s pH 24) What would be the resulting pH if one drop (0.05 ml) of 1.0 M HCl was added to one liter of pure water (assume pH 7.0)? A) 2.7 B) 4.3 C) 5.0 D)7.0 (there would be no significant change) E) 9.7 Answer: B Difficulty: Hard Section Reference: 2-3 Learning Objective:Calculate the effect of acids and bases on a solution’s pH 25) What would be the resulting pH if one mlof 1.0 M NaOH was added to one liter of pure water (assume pH 7.0)? A) 1 B) 3 C) 7.3 D) 11 E) 13 Answer: D Difficulty: Medium Section Reference: 2-3 Learning Objective:Calculate the effect of acids and bases on a solution’s pH 26) Which of the following would be the strongest acid? A)formic acid, pK=3.75 B) succinic acid, a diprotic acid with pK=4.21 and 5.64 C)acetic acid, pK=4.76 D)ammonium ion, pK=9.25 E)cannot be determined from the given information Answer: A Difficulty: Easy Section Reference: 2-3 Learning Objective:Calculate the effect of acids and bases on a solution’s pH 27) What is the pH of a solution that contains three parts of acetic acid and one part sodium acetate? The pK for acetic acid is 4.76. A) 5.24 B) 5.06 C) 4.46 D) 4.28 E)cannot be determined from the given information Answer: D Difficulty: Medium Section Reference: 2-3 Learning Objective:Calculate the effect of acids and bases on a solution’s pH 28) If the pK values for phosphoric acid are 2.15, 6.82 and 12.38, at what pH would one observe equal amounts of H2PO4- and HPO42-? A) 2.15 B) 4.49 C) 6.82 D) 9.60 E) 12.38 Answer: C Difficulty: Medium Section Reference: 2-3 Learning Objective:Calculate the effect of acids and bases on a solution’s pH 29) If 1.0 mL of 1.0 M acetic acid (pK = 4.76, K = 1.74 x 10–5) was added to one liter of pure water, what is the resulting pH? A) 1.0 B) 1.3 C) 3.0 D) 3.9 E) 10.1 Answer: D Difficulty: Hard Section Reference: 2-3 Learning Objective:Calculate the effect of acids and bases on a solution’s pH 30) If the pK values for phosphoric acid are 2.15, 6.82 and 12.38, _____ would predominate at pH 5 while _____ would predominate at pH 10. A) H3PO4; H2PO4B) H3PO4; HPO42C) H3PO4; PO43D) H2PO4-; PO43E) H2PO4-; HPO42Answer: E Difficulty: Medium Section Reference: 2-3 Learning Objective:Calculate the effect of acids and bases on a solution’s pH 31) What is the conjugate acid of H2PO4-? A) HPO42B) H2PO4 C) H3PO4 D) PO43E)none of the above Answer: C Difficulty: Easy Section Reference: 2-3 Learning Objective:Calculate the effect of acids and bases on a solution’s pH 32) Considering a 0.1 M formic acid buffer, what is the concentration of formic acid present in a solution of pH 4.25 if the pK of formic acid is 3.75? A) 0.024 M B) 0.033 M C) 0.067 M D) 0.076 M E)none of the above Answer: A Difficulty: Hard Section Reference: 2-4 Learning Objective:Describe how buffer solutions resist changes in pH 33) Which of the following shows the buffer that is found in the blood stream? A) H3PO4 B) H2PO4C) HPO42D) H2CO3 E) HCO3- H2PO42- + H+ HPO42- + H+ PO43- + H+ HCO3- + H+ CO32- + H+ Answer: D Difficulty: Medium Section Reference: 2-4 Learning Objective:Describe how buffer solutions resist changes in pH 34) Which of the following shows the intracellular buffer? A) H3PO4 B) H2PO4C) HPO42D) H2CO3 E) HCO3- H2PO42- + H+ HPO42- + H+ PO43- + H+ HCO3- + H+ CO32- + H+ Answer: B Difficulty: Medium Section Reference: 2-4 Learning Objective:Describe how buffer solutions resist changes in pH 35) If a phosphate buffer (pK=6.82) was formulated such that its pH was 7.3, it would be best suited to buffer against _____. If instead, it was formulated such that its pH was 6.3, it would be best suited to buffer against _____. A)acid; base B)acid; acid C)base; acid D)base; base E)a buffer with a pH that far from the pK would not be an effective buffer Answer: A Difficulty: Hard Section Reference: 2-4 Learning Objective:Describe how buffer solutions resist changes in pH 36) Which of the following could be used to formulate 100 mls of a 0.10 M acetate buffer (pK=4.76) at pH 5 if you start with 64 mls of 0.10 M sodium acetate? A) 3.6 mls of 1 M HCl B) 3.6 mls of 1 M NaOH C) 34 mls of 0.10 M HCl D) 34 mls of 0.10 M NaOH E) 34 mls of 0.10 M acetic acid Answer: E Difficulty: Hard Section Reference: 2-4 Learning Objective:Describe how buffer solutions resist changes in pH 37) Which of the following could be used to formulate 100 mls of a 0.10 M phosphate buffer (pK=6.82) at pH 7.2? A) 2.9 mmoles of Na2HPO4 and 7.1 mmoles of NaHPO4 B) 10 mmoles of Na2HPO4 and 7.1 mmoles of NaOH C) 10 mmoles of NaHPO4 and 7.1 mmoles of HCl D) 10 mmoles of H3PO4 and 17.1 mmoles of NaOH E) all of the above Answer: E Difficulty: Hard Section Reference: 2-4 Learning Objective:Describe how buffer solutions resist changes in pH 38) Metabolic acidosis often causes increased respiratory rates. What portion of the bloodstream buffer is lost through increased respiration? A) H+ B) HCO3- C) H2CO3 D) CO2 E) H2O Answer: D Difficulty: Easy Section Reference: 2-4 Learning Objective:Describe how buffer solutions resist changes in pH 39) What is the resulting pH if 10 millimoles of HCl is added to 1 liter of a 0.1 M phosphate buffer at pH 7.00 (pK=6.82)? A) 6.82 B) 6.98 C) 7.01 D) 7.19 E)cannot be determined Answer: A Difficulty: Hard Section Reference: 2-4 Learning Objective:Describe how buffer solutions resist changes in pH 40) During vigorous exercise, hydrogen ions are produced within cells as a result of increased metabolism. What component of the intracellular buffer would increase as a result of the increased H+ production? A) H3PO4 B) H2PO4C) HPO42D) PO43E)none of the above Answer: B Difficulty: Medium Section Reference: 2-4 Learning Objective:Describe how buffer solutions resist changes in pH