A. the products of the reaction are more complex than the reactants.
B. the system takes up heat from its surroundings.
C. the products of the reaction are more disordered than the reactants.
D. the system gains free energy.
2. If a chemical reaction starts with 1M concentrations each of reactants A and B and products C and D, under what conditions of K'eq and DG'o will the reaction proceed in the forward direction (DG'o = RT ln K'eq)?
A. If K'eq is greater than 1 and DG'o is negative.
B. If K'eq is 0 and DG'o is negative.
C. If K'eq is negative and DG'o is negative.
D. If K'eq is less than 1 and DG'o is positive.
3. Living cells and organisms
A. exchange energy but not matter with their surroundings.
B. exchange energy and material with their surroundings.
C. are closed systems.
D. are at equilibrium with their surroundings.
4. The standard free-energy changes of two sequential chemical reactions are additive only if
A. the reactions share a common intermediate.
B. each reaction has a negative DG' o.
C. the overall (net) reaction has a postive DG' o.
D. the exergonic reaction occurs first.
5. Which of the following has a thioester bond?
A. PEP (phosphoenolpyruvate)
B. ATP
C. phosphocreatine
D. acetyl-CoA
6. What provides the energy for the synthesis in an RNA polymer?
A. The transfer of an energy-rich ribonucleoside monophosphate to the polymer.
B. The hydrolysis of two anhydride bonds in ribonucleoside triphosphates.
C. The transfer of the g phosphate of a ribonucleoside triphosphate to the polymer.
D. The transfer of an energy-rich ribonucleoside triphosphate to the polymer.
7. When a nucleophile attacks the a phosphorous atom of ATP, what kind of transfer occurs?
A. pyrophosphoryl transfer
B. phosphoryl transfer
C. adenylyl transfer
D. adenosine transfer
8. When dNTPs become depleted in the cell, which of the following enzymes will regenerate dNTPs from dNDPs?
A. nucleoside diphosphate kinase
B. polyphosphate kinase
C. creatine kinase
D. adenylate kinase
9. Which of the following enzymes can catalyze the conversion of AMP to ADP?
A. nucleoside diphosphate kinase
B. polyphosphate kinase
C. creatine kinase
D. adenylate kinase
10. Conversion of NAD+ to NADH is accomplished by the addition of
A. a proton.
B. an electron.
C. a hydride ion.
D. a hydrogen atom.
11. Which of the following carbon-containing molecules is most fully oxidized?
A. carbon monoxide
B. carbon dioxide
C. methane
D. ethanol
12. The oxidation-reduction reaction Fe2++ Cu2+
Fe3++ Cu+, can be described in terms of two half-reactions:(1) Fe2+
Fe3+ + e-(2) Cu2+ + e-
Cu+Which of the following statements is true?
A. In the overall reaction at the top, the cupric ion (Cu2+) is the reducing agent.
B. In half-reaction (2), cupric ion (Cu2+) is being oxidized.
C. In half-reaction (1), Fe3+ and e- constitute a conjugate redox pair.
D. In the overall reaction at the top, the ferrous ion (Fe2+) is oxidized by the cupric ion (Cu2+).
13. Electrons can be transferred from one molecule (electron donor) to another molecule (electron acceptor) by all of the following ways except
A. as a hydride ion.
B. directly as an electron.
C. as a proton.
D. as a hydrogen atom.
14. Which of the following is true of flavin nucleotides?
A. They have no reduction potential unless bound to a protein.
B. They always accept two electrons.
C. They are utilized by oxygenases.
D. They act as prosthetic groups.
15. Below are the standard reduction potentials (E'o) for two conjugate redox pair:
Pyruvate-/lactate- E'o = –0.185
NAD+/NADH E'o = –0.320
Which of the following is true?
A. The pyruvate/lactate conjugate redox pair has a greater tendency to lose electrons than the NAD+/NADH redox pair.
B. Pyruvate has a greater affinity for electrons than NAD+.
C. NAD+ is a reducing agent.
D. Under standard conditions, NAD+ is more likely to be converted to NADH, than pyruvate is to converted to lactate.
sources: Lehninger's principle of biochemistry
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