85. Which of the following radicals is the most stable?
(A)
(B)
(C)
(D)
(E)

81. Why does the pH value afiect the separation of amino acids by electrophoresis? Please choose tiie wrong reason. (A) Amino acids exist as zwitterions. (B) At low pH values, the amino acid molecules will be strongly attracted to the negative electrode. (C) At high pH values, the amino add molecules will be strongly attracted to the negative electrode. (D) In basic solution, the net chaise is negative due to die dissociation of the carboxylic acid groups. (E) None of the above.

82. What is a virtual state in Raman spectroscopy? Please choose the correct description. (A) It helps us to visualize both elastic and inelastic scattering processes. (B) It lies between the ground state and a vibrational state of tfie molecule. (C) It is also a first vibrational state. (D) It is a real electronic energy state. (E) None of die above.

83. Sort the following compounds in decreasing order by their pKa valuesCfrom highest to lowest). (A) I＞Ⅱ＞Ⅲ＞Ⅳ(B) IV＞Ⅲ＞Ⅱ＞I(C)IV＞Ⅱ＞Ⅲ＞I (D)Ⅲ＞I＞Ⅱ＞IV(E)I＞Ⅲ＞Ⅱ＞I

84. Which of the reactions below shows the correct usage of curly arrows? (A)(B)(C)(D)(E)

86. Disulfide linkages can form between________ . (A) two cysteine residues (B) two methionine residues (C) a cysteine residue and a methionine residue (D) two ttireonine residues (E) a methionine residue and a flireonine residue

87. What is the electron configuration for the barium atom? (A) 1s22s22p63p64s2 (B) 1s22s22p63s23p64s1 (C) 1s22s22p63s23p63d104s2(D) [Xe] 6s2 (E) 1 s22s22p63s2

88. Choose the correct statement. (A) A reaction that exhibits a negative value of △S cannot be spontaneous. (B) Exothermic reactions are always spontaneous. (C) Free energy is independent of temperature, (D) At constant pressure and temperature, a decrease in free energy ensures an increase in the entropy of the system. (E) None of the above.

89. Which of the following statements is true about the ionization energy ofMg+? (A) It will be equal to the negative value of the electron affinity ofMg. (B) It will be equal to the negative value of the electron aflfinity of Mg+・ (C) It will be equal to the ionization energy of Li. (D) It will be equal to the negative value of the electron affinity of Mg2+. (E) None of the above.

90. Please choose the correct description for confidence level. (A) Confidence level is the probability that the sample mean lies within a certain interval. (B) Confidence level is the probability that the true mean lies within a certain interval. (C) Confidence level is the range of values within which the population mean is expected to lie with a certain probability. (D) Confidence level is the range of values within which the true value is expected to lie with a certain probability, (E) None of the above.

1. Which of the following is NOT a cytoskeleton protein? (A) Actin, (B) Microtubule, (C) Intermediate filament, (D) Syntaxin, (E) Spectrin