Final Exam
Final Biochemistry Exam Select the best answer for the following questions.
1. Which group of single-celled microorganisms has many members found growing in extreme environments?
A) Bacteria B) Archaea C) Eukaryotes D) Heterotrophs E) None of the above
2. The three-dimensional structure of macromolecules is formed and maintained primarily through noncovalent interactions. Which one of the following is not considered a noncovalent interaction?
A) carbon-carbon bonds B) hydrogen bonds C) hydrophobic interactions D) ionic interactions E) van der Waals interactions
3. Dissolved solutes alter some physical (colligative) properties of the solvent water because they change the:
A) concentration of the water. B) hydrogen bonding of the water. C) ionic bonding of the water. D) pH of the water. E) temperature of the water.
4. The pH of a sample of blood is 7.4, while gastric juice is pH 1.4. The blood sample has:
A) 0.189 times the [H+] as the gastric juice. B) 5.29 times lower [H+] than the gastric juice. C) 6 times lower [H+] than the gastric juice. D) 6,000 times lower [H+] than the gastric juice. E) a million times lower [H+] than the gastric juice.
5. Phosphoric acid is tribasic, with pKa’s of 2.14, 6.86, and 12.4. The ionic form that predominates at pH 3.2 is:
A) H3PO4. B) H2PO4–. C) HPO42–. D) PO43–. E) PO-.
6. The aqueous solution with the highest pH is:
A) 1 M HCl. B) 1 M NH3 (pKa = 9.25). C) 0.5 M NaHCO3 (pKa = 3.77). D) 0.1 M NaOH. E) 0.001 M NaOH.
7. Titration of valine by a strong base, for example NaOH, reveals two pK’s. The titration reaction occurring at pK2 (pK2 = 9.62) is:
A) —COOH + —NH2 → —COO− + —NH2+. B) —COO− + —NH2+ → —COOH + —NH2. C) —NH3+ + OH− → —NH2 + H2O. D) —NH2 + OH− → —NH− + H2O. E) —COOH +
1. Which group of single-celled microorganisms has many members found growing in extreme environments?
A) Bacteria B) Archaea C) Eukaryotes D) Heterotrophs E) None of the above
2. The three-dimensional structure of macromolecules is formed and maintained primarily through noncovalent interactions. Which one of the following is not considered a noncovalent interaction?
A) carbon-carbon bonds B) hydrogen bonds C) hydrophobic interactions D) ionic interactions E) van der Waals interactions
3. Dissolved solutes alter some physical (colligative) properties of the solvent water because they change the:
A) concentration of the water. B) hydrogen bonding of the water. C) ionic bonding of the water. D) pH of the water. E) temperature of the water.
4. The pH of a sample of blood is 7.4, while gastric juice is pH 1.4. The blood sample has:
A) 0.189 times the [H+] as the gastric juice. B) 5.29 times lower [H+] than the gastric juice. C) 6 times lower [H+] than the gastric juice. D) 6,000 times lower [H+] than the gastric juice. E) a million times lower [H+] than the gastric juice.
5. Phosphoric acid is tribasic, with pKa’s of 2.14, 6.86, and 12.4. The ionic form that predominates at pH 3.2 is:
A) H3PO4. B) H2PO4–. C) HPO42–. D) PO43–. E) PO-.
6. The aqueous solution with the highest pH is:
A) 1 M HCl. B) 1 M NH3 (pKa = 9.25). C) 0.5 M NaHCO3 (pKa = 3.77). D) 0.1 M NaOH. E) 0.001 M NaOH.
7. Titration of valine by a strong base, for example NaOH, reveals two pK’s. The titration reaction occurring at pK2 (pK2 = 9.62) is:
A) —COOH + —NH2 → —COO− + —NH2+. B) —COO− + —NH2+ → —COOH + —NH2. C) —NH3+ + OH− → —NH2 + H2O. D) —NH2 + OH− → —NH− + H2O. E) —COOH +