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 1. How can a basic group act as a acid? A. By accepting electrons * B. By donating protons C. By donating hydrogen bonds D. By accepting protons E. Basic groups can never act as a acid Correct Answer: B 2. Which of the following best describes the type of compound ATP is? A. Phospholipid B. Imino acid * C. Nucleotide D. Carbohydrate E. Amino acid Correct Answer: C 3 ‐ 5. Match the items in the alphabetic list to the numbered items. A. Polysaccharide B. Proteins C. Nucleic acid 3. Encode information 4. Carry out metabolic reactions 5. Energy store Correct Answer: 3:C 4:B 5:A 6 ‐ 9. Match the items in the alphabetic list to the numbered items. A. Amino acid B. Imino acid C. Amino aldehyde D. Amide 6. 7. 8. 9. Correct Answer: 6:B 7:A 8:D 9:C 10. What class of biomolecule is structure (b) in panel A? A. Amino Acid * B. Nucleotide C. Monosaccharide D. Disaccharide E. Lipid Correct Answer: B 11. What functional group(s), named below, is(are) present in the compound shown in (a) panel A? A. Ester linkage B. Imine group * C. Amido group D. Carboxylate group E. All functional groups listed are present in the molecule Correct Answer: C 12. Which compound(s) shown in the panel A contains a ether linkage? A. A B. B C. D * D. A & B E. A, B and D Correct Answer: D 13. Which compound(s) shown in the panel A contains an amino and carboxylate group? A. A B. B * C. C D. A B and C Correct Answer: C 14. Which compound(s) shown in panel A is(are) monosaccharide(s)? * A. A B. B C. C D. D E. A & B Correct Answer: A 15. Which of the following is a universal characteristic of water‐soluble organic compound? A. They are composed of carbon and hydrogen atoms. B. They must contain a group that has a full negative charge. C. They must contain a group that has a full positive charge. * D. They contain a polar group that can hydrogen bond with water. E. They contain aromatic group. Correct Answer: D 16. Which structure(s) below is(are) amino acid(s)? A
B
O
O
N
N
O
C
D
O
O
N
N
A. A, B, C, and D B. A, C and D C. A and D * D. D E. C and D Correct Answer: D O
N
N
17. Which option below is FALSE, regarding difference in Gibbs free energy between two states? A. DG = DH ‐ TDS * B. Unfavorable reactions have DG < 0 C. The change in free energy does not depend on the path between the two states D. The value of DG varies with changes in temperature Correct Answer: B 18. Which of the following terms has(have) units of energy? A. Delta H B. Enthalpy C. Gibbs free energy D. T DS * E. All of the options represents parameters that have units of energy Correct Answer: E 19. Which of the following processes are NEVER spontaneous? A. A reaction that occurs with any size decrease in enthalpy and any size increase in entropy B. A reaction that occurs with a small increase in enthalpy and a larger increase in entropy C. A reaction that occurs with a large decrease in enthalpy and a small decrease in entropy * D. A reaction that occurs with any size increase in enthalpy and any size decrease in entropy Correct Answer: D 20. A system defined by individual molecules of octane hydrated by water. This system undergoes a spontaneous transformation where octane molecules aggregate in water. What statement about thermodynamic parameteres is true? A. Enthalpy changes contributes most to free energy change * B. Entropy changes contribute the most to free energy change C. Entropy and enthalpy changes contribute equally to free energy change D. Increases in temperature make this process non‐sponteneous Correct Answer: B 21. Thermodynamically biochemical systems tend to: A. Maximize energy B. Minimize temperature C. Maximize Gibb's Free energy * D. Maximize entropy E. All of the above Correct Answer: D 22. Question Name: thermo3 Type: MC Objective: Oliveira Item Bank: Biochemistry (PHAR3316) EXAM1 What is the entropy change in water evaporation? * A. Positive B. Negative C. Zero D. Impossible to be determined Correct Answer: A 23. What is the entropy change in the dissolution of MgCl2 in water? * A. Positive B. Negative C. Zero D. Impossible to be determined Correct Answer: A 24. What statement(s) below is(are) TRUE: I ‐ A reaction is said to be spontaneous when it can proceed in either the forward or reverse direction II ‐ A non‐spontaneous reaction will proceed spontaneously in the reverse direction III ‐ A spontaneous process always occurs very rapidly A. I only * B. II only C. III only D. I and II E. I, II and III Correct Answer: B 25. Which of the statements below best describes hydrogen bonds found in liquid water? * A. H‐bonds are dipole‐dipole interactions B. H‐bonds are attractions between the protons attached to oxygen nuclei C. H‐bonds are attractions between two hydrogen atoms D. H‐bonds are attractions between H+ and OH‐ ions found in liquid water E. H‐bonds are ion‐induced dipole interactions Correct Answer: A 26. Which statement about pK is true? A. When pK is equal to the pH their is minimal buffering capacity B. When pK is equal to the pH, [HA]= 2 [A‐] * C. The pK is equal to the pH at the midpoint of the titration. D. All of the choices given are correct Correct Answer: C 27. What are the requirements for hydrophobic interactions between nonpolar molecules or groups? A. Strong induced dipoles between nonpolar groups B. The establishment of strong C‐H dipoles * C. The presence of a polar solvent D. Maximizing interactions of water molecules with non‐polar molecules E. A strong repulsion between water and nonpolar groups Correct Answer: C I gave everyone points for this question (Remember that water and non‐polar compounds are unable to interact with each other) 28. What statement is TRUE regarding hydrongen bond between water and a biomolecule? A. The hydrogen ion on the water molecule forms an ionic bond with a hydride ion on the biomolecule B. A hydrogen on the water molecule forms a covalent bond with a electronegative atom in the biomolecule * C. The hydrogen bond will tipically form between an oxygen atom of water and either a nitrogen, sulfur or oxygen atom of a biomolecule that has a hydrogen to donate D. The partial charge on the hydrogen atom of the water molecule interacts with the partial charge on the hydrogen atom of the biomolecule Correct Answer: C 29. What point in the titration curve shown in panel B represents the titration of the first group of the amino acid aspartate shown in the diagram? * A. A B. B C. C D. D E. A & C Correct Answer: A 30. Considering the titration of the amino acid Aspartate shown in panel B, how many protons are being abstrated during the full titration of this amino acid? A. 0.5 B. 1 C. 2 D. 2.5 * E. 3 Correct Answer: E 31. Question Name: Weak acid Type: MC Objective: exam2 Item Bank: Marcos_Biochem_08_exam2 At what pH is the R group of tyrosine 50% deprotonate? (pKa for Tyr R group is 10.5, structure shown below) *A. pH=pKa B. pH=pKa‐1 C. pH>pKa+1 D. pH<pKa E. Tyr side chain cannot be deprotonated Correct Answer:A 32. Which of the molecules shown in panel C is non‐polar? A. a B. b C. c * D. d E. e Correct Answer: D 33. Which molecule(s) shown in panel C is(are) amphiphilic? A. A B. B & C C. A & B D. B & D & E * E. A & B & E Correct Answer: E 34. For an acid with a pK of 4, the ratio of the acid (HA) to its corresponding base (A‐) at pH 6 is: A. 100 B. 10 C. 1 D. 0.1 E. 0.01 Correct Answer: E I added points for this question for all the class those who got it right received extra points 35. At physiological pH (7.4), what is the approximate [H+] of the solution? A. ‐7.4 B. 0.6 C. 0.6 X 10‐8 D. 1.0 X 10‐8 * E. 4.0 X 10‐8 Correct Answer: E 36. Thermodynamically what is the consequence of an increase in disorder? A. This is a characteristic of an system increasing enthalpy B. This results in a decrease in entropy C. This is a requirement for a process to be spontaneous * D. This results in the term T DeltaS being positive E. This is found in every exergonic process Correct Answer: D CANCELLED BELOW 37. When is the reaction for the conversion of reactant A to product B favorable? A : H(kJ/mol) = 54 S(J K‐1 mol‐1) = 22 B: H(kJ/mol) = 60 S(J K‐1 mol‐1) = 43 A. above 37 degrees centigrate B. above 4 degree centigrate C. above 100 degree centigrate D. above 218 degree centigrate Correct Answer: CANCELLED 38. At pH 4.5 the relative concentrations of H3PO4, H2PO4‐1 and HPO4‐2 are: (See panel D). A. [H3PO4] >> [H2PO4‐1] > [HPO4‐2]. B. [H3PO4] << [H2PO4‐1] = [HPO4‐2]. C. [H3PO4] > [H2PO4‐1] < [HPO4‐2]. *D. [H3PO4] < [H2PO4‐1] > [HPO4‐2]. Correct Answer: D This is the third question that I decided to include as extra credit 39. 10 fold decrease in the proton concentration would: A. Decrease the pH by 1 unit B. Increase the pH by 0.1 unit C. Decrease the pH 10 units D. Decrease the pH by 2 units * E. Increase the pH by 1 units Correct Answer: E 40. When the pH for a solution of a weak acid is equal to its pK, the ratio of the concentrations of the HA/A‐ is? A. 0 * B. 1 C. 2 D. 3 E. 4 Correct Answer: B 41. The ΔG for the process depicted in panel E where reactants are transformed into products is shown in the free energy diagram. What can be said about the change in free energy for this process which can occur in either of two paths? A. The delta G is maller for path B B. The delta G is smaller for path A * C. The delta G is the same for both paths D. The delta G is largest for path A E. The delta G is largest for path B Correct Answer: C Points for this section of the exam were computed as follows: [ Number of correct answers + 3 (as indicated above) ] * 1.8 e.g. (41+3)*1.8 = 79.2 points (4.2 extra points from the official 75 points) PANEL A E D A B C PANEL B PANEL C Titration of Phosphate
Phosphoric acid
pK
H3PO4
Phosphate, monobasic H2PO4-1
Phosphate, dibasic
HPO4-2
  H2PO4-1
2.0
  HPO4-2
6.5

PO4-3
12.5
PANEL D – Titration of Phosphate PANEL E Path A: dashed line products Gibbs Free energy Path B: solid line reactants Reaction coordinate