BIOCHEM ACS STUDY GUIDE
Each of the following subcellular structures contains DNA EXCEPT
A. the nucleus. B. ribosomes. C. chloroplasts. D. mitochondria. - Answer- B
In plant and animal cells, the three-dimensional integrity of the cell is maintained, in part, by an internal network of filaments called A. the cell wall. B. the Golgi apparatus. C. the cytoskeleton. D. the endoplasmic reticulum. - Answer- C
Of the following, which are prokaryotes?
A. viruses B. bacteria C. yeast D. plant cells - Answer- B
G° for the conversion of glycerol-3-phosphate to glycerol + Pi is -2.2 kcal/mole. Thus, you can conclude that
A. this reaction will occur spontaneously.
B. this reaction may or may not occur spontaneously, depending on the actual concentrations of reactants and products.
C. this reaction will only occur spontaneously if it is coupled to
another reaction that has a more favorable G°.
D. this reaction is so strongly favorable that it could be coupled to drive an otherwise unfavorable cell reaction. - Answer- B
In most biochemical reactions, ∆PV is
A. negligible
B. positive
C. negative
D. dependent on ∆E - Answer- A According to the Second Law of Thermodymnamics, A. the total entropy change in any reaction that occurs spontaneously must be greater than 0. B. the total entropy change in any reaction that occurs spontaneously must be less than 0. C. the total entropy of the universe remains constant. D. the total entropy of the universe is always decreasing. - Answer- A
Which of the following is true? A. Liquid and solid water have the same number of hydrogen bonds per molecule of water B. Liquid water has more hydrogen bonds per molecule than does solid water C. Solid water has more hydrogen bonds per molecule than does liquid water D. Hydrogen bonding is a major factor in the structure of gaseous water E. None is true - Answer- C
What is the pH of an aqueous solution that has a [OH-] of 3.45 x 10-5 M? A. 3.47 B. 4.47 C. 5.53 D. 9.54 E. none of the above - Answer- D
A peptide was found to have a molecular mass of about 650 and upon hydrolysis produced Ala, Cys, Lys, Phe, and Val in a 1:1:1:1:1 ratio. The peptide upon treatment with Sanger's reagent produced DNP-Cys and exposure to carboxypeptidase produced valine. Chymotrypsin treatment of the peptide produced a dipeptide that contained sulfur and has a UV absorbance, and a tripeptide. Exposure of the peptide to trypsin produced a dipeptide and a tripeptide. Deduce the sequence of the peptide. A. Val-Ala-Lys-Phe-Cys B. Cys-Lys-Phe-Ala-Val C. Cys-Ala-Lys-Phe-Val D. Cys-Phe-Lys-Ala-Val E. Val-Phe-Lys-Ala-Cys - Answer- D
Which amino acid has an R-group pKa closest to physiological pH? A. lysine B. histidine C. glutamate D. arginine E. aspartate - Answer- B
Which is true regarding the orientation of the R-groups in beta structures? A. In the parallel beta sheet structures the amino acid R-groups are all on the same side of the sheet. B. In the antiparallel beta sheet structure the R-groups on alternate strands are on the same side of the sheet. C. In parallel and antiparallel sheets consecutive R-groups on each peptide strand alternate sides of the sheet. D. Because of the free rotation around the alpha carbon, the R-groups can seek the least crowded region and are not restricted to specific side of the sheet. E. a and b - Answer- C
A reagent commonly employed to cleave disulfide bonds in proteins is A. 2,4-dinitrofluorobenzene B. urea C. 2-mercaptoethanol D. phenylisothiocyanate E. cyanogen bromide - Answer- C
With respect to a relaxed muscle, which of the following is true? A. the number of actin-myosin cross-bridges is maximized and the muscle is shortened B. the number of actin-myosin cross bridges is maximized and the muscle is stretched C. the number of actin-myosin cross bridges is minimized and the muscle is shortened D. the number of actin-myosin cross bridges is minimized and the muscle is stretched E. none of the above - Answer- D
Which of the following does not describe hemoglobin? A. Hemoglobin is an oxygen transport protein. B. Hemoglobin is an allosteric protein. C. Hemoglobin has quaternary structure. D. Copper ions are important in hemoglobin's ability to bind oxygen. E. Hemoglobin is composed, in part, of an iron containing heme group. - Answer- D
Which of the following would allow you to determine the isoelectric point of a protein? A. protein quaternary structure B. protein solubility as a function of pH C. protein size D. protein shape E. protein tertiary structure - Answer- B
A mixture of urease (pI = 5.1, mol. wt. 482,700), catalase (pI = 5.6 mol. wt. 247,500), lactoglobin (pI 5.2, mol. wt. 37,100) and hemoglobin (pI 6.9, mol. wt. 64,500) were applied in a pH 6.5 buffer to a DEAE-cellulose chromatography column and eluted with the same buffer. What was their order of elution?
A. urease, lactoglobin, catalase, hemoglobin
B. hemoglobin, catalase, lactoglobin, urease
C. urease, catalase, hemoglobin, lactoglobin
D. lactoglobin, hemoglobin, catalase, urease
Each of the following subcellular structures contains DNA EXCEPT
A. the nucleus. B. ribosomes. C. chloroplasts. D. mitochondria. - Answer- B
In plant and animal cells, the three-dimensional integrity of the cell is maintained, in part, by an internal network of filaments called A. the cell wall. B. the Golgi apparatus. C. the cytoskeleton. D. the endoplasmic reticulum. - Answer- C
Of the following, which are prokaryotes?
A. viruses B. bacteria C. yeast D. plant cells - Answer- B
G° for the conversion of glycerol-3-phosphate to glycerol + Pi is -2.2 kcal/mole. Thus, you can conclude that
A. this reaction will occur spontaneously.
B. this reaction may or may not occur spontaneously, depending on the actual concentrations of reactants and products.
C. this reaction will only occur spontaneously if it is coupled to
another reaction that has a more favorable G°.
D. this reaction is so strongly favorable that it could be coupled to drive an otherwise unfavorable cell reaction. - Answer- B
In most biochemical reactions, ∆PV is
A. negligible
B. positive
C. negative
D. dependent on ∆E - Answer- A According to the Second Law of Thermodymnamics, A. the total entropy change in any reaction that occurs spontaneously must be greater than 0. B. the total entropy change in any reaction that occurs spontaneously must be less than 0. C. the total entropy of the universe remains constant. D. the total entropy of the universe is always decreasing. - Answer- A
Which of the following is true? A. Liquid and solid water have the same number of hydrogen bonds per molecule of water B. Liquid water has more hydrogen bonds per molecule than does solid water C. Solid water has more hydrogen bonds per molecule than does liquid water D. Hydrogen bonding is a major factor in the structure of gaseous water E. None is true - Answer- C
What is the pH of an aqueous solution that has a [OH-] of 3.45 x 10-5 M? A. 3.47 B. 4.47 C. 5.53 D. 9.54 E. none of the above - Answer- D
A peptide was found to have a molecular mass of about 650 and upon hydrolysis produced Ala, Cys, Lys, Phe, and Val in a 1:1:1:1:1 ratio. The peptide upon treatment with Sanger's reagent produced DNP-Cys and exposure to carboxypeptidase produced valine. Chymotrypsin treatment of the peptide produced a dipeptide that contained sulfur and has a UV absorbance, and a tripeptide. Exposure of the peptide to trypsin produced a dipeptide and a tripeptide. Deduce the sequence of the peptide. A. Val-Ala-Lys-Phe-Cys B. Cys-Lys-Phe-Ala-Val C. Cys-Ala-Lys-Phe-Val D. Cys-Phe-Lys-Ala-Val E. Val-Phe-Lys-Ala-Cys - Answer- D
Which amino acid has an R-group pKa closest to physiological pH? A. lysine B. histidine C. glutamate D. arginine E. aspartate - Answer- B
Which is true regarding the orientation of the R-groups in beta structures? A. In the parallel beta sheet structures the amino acid R-groups are all on the same side of the sheet. B. In the antiparallel beta sheet structure the R-groups on alternate strands are on the same side of the sheet. C. In parallel and antiparallel sheets consecutive R-groups on each peptide strand alternate sides of the sheet. D. Because of the free rotation around the alpha carbon, the R-groups can seek the least crowded region and are not restricted to specific side of the sheet. E. a and b - Answer- C
A reagent commonly employed to cleave disulfide bonds in proteins is A. 2,4-dinitrofluorobenzene B. urea C. 2-mercaptoethanol D. phenylisothiocyanate E. cyanogen bromide - Answer- C
With respect to a relaxed muscle, which of the following is true? A. the number of actin-myosin cross-bridges is maximized and the muscle is shortened B. the number of actin-myosin cross bridges is maximized and the muscle is stretched C. the number of actin-myosin cross bridges is minimized and the muscle is shortened D. the number of actin-myosin cross bridges is minimized and the muscle is stretched E. none of the above - Answer- D
Which of the following does not describe hemoglobin? A. Hemoglobin is an oxygen transport protein. B. Hemoglobin is an allosteric protein. C. Hemoglobin has quaternary structure. D. Copper ions are important in hemoglobin's ability to bind oxygen. E. Hemoglobin is composed, in part, of an iron containing heme group. - Answer- D
Which of the following would allow you to determine the isoelectric point of a protein? A. protein quaternary structure B. protein solubility as a function of pH C. protein size D. protein shape E. protein tertiary structure - Answer- B
A mixture of urease (pI = 5.1, mol. wt. 482,700), catalase (pI = 5.6 mol. wt. 247,500), lactoglobin (pI 5.2, mol. wt. 37,100) and hemoglobin (pI 6.9, mol. wt. 64,500) were applied in a pH 6.5 buffer to a DEAE-cellulose chromatography column and eluted with the same buffer. What was their order of elution?
A. urease, lactoglobin, catalase, hemoglobin
B. hemoglobin, catalase, lactoglobin, urease
C. urease, catalase, hemoglobin, lactoglobin
D. lactoglobin, hemoglobin, catalase, urease
