Biology exam 2 2009 - Biology 181R Sections 5, 6H Brian...

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Biology 181R Sections 5, 6H Brian Larkins and Ramin Yadegari Hour Exam #2 October 9, 2009 (version 1 key) 1. Which of the following describes the first law of thermodynamics? a. The entropy of the universe is constantly increasing b. Energy cannot be transferred or transformed c. Energy cannot be created or destroyed d. A change in entropy is affected by the temperature e. At absolute zero, there is no change in entropy 2. Which of the following statements describes the laws of thermodynamics as they apply to living organisms? a. The energy content of an organism remains constant throughout its life b. Because entropy is constantly increasing in cells, the organism must continuously supply energy to maintain itself. c. The second law of thermodynamics does not apply to living organisms d. The entropy of an organism declines as the organism grows in complexity 3. What explains the evolution of multiple enzymatic steps in glycolysis and the Krebs cycle, rather than a single reaction that converts glucose into carbon dioxide and water? a. Enzymes are typically able to perform single rather than multiple modifications of substrates. b. With multiple enzymes more heat can be released from the reaction. c. The multi-enzyme approach more effectively captures the potential energy of glucose d. A and b e. A and c 4. Which of the following statements is (are) true about enzyme-catalyzed reactions? a. The reaction is faster when an enzyme is involved b. The amount of free energy released is greater when an enzyme is involved. c. An enzyme catalyzed reaction is always exergonic, releasing free energy d. All of the above are true e. None of the above are true 5. Which of the following affects the rate of an enzyme catalyzed reaction? a. The concentration of the substrate b. The pH of the solution in which it occurs c. The concentration of the products d. Reversible inhibitors e. All of the above are true 6. Co-enzymes are organic molecules that bind at an enzyme’s active site and participate in the chemical reaction. Which of the following is an example of a co- enzyme? a. ATP
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b. NAD c. Coenzyme A d. FAD e. All of the above are true 7. Consider the following reaction: sucrose ↔glucose + fructose The equilibrium constant (Keq) for the hydrolysis of sucrose in this equation is 140,000. This implies the reaction will _______________-. a. Be endergonic b. Have a + ΔG c. Not be spontaneous d. Predominantly proceed to the left e. None of the above is true 8. In the reaction A + NAD →B + NADH + H+, it stands to reason that ____________. a. Compound A is being reduced b. NAD is being reduced c. Compound A must have a higher free energy than compound B d. A is the reducing agent and B is the oxidizing agent e. All of the above are true. 9.
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This note was uploaded on 11/17/2011 for the course BIO 12334343 taught by Professor Jony during the Fall '09 term at University of Arizona- Tucson.

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Biology exam 2 2009 - Biology 181R Sections 5, 6H Brian...

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