Chapter 1 Introduction to the Chemistry of Life Multiple Choice

Multiple Choice 11. What are the four most abundant elements in a human body? A) C, N, O, H B) C, N, O, P C) C, S, O, H D) C, Na, O, H E) none of the above Ans: A Level of Difficulty: Moderate Section: 1.1.A Learning objective: The Origin of Life 12. The atmosphere of prebiotic earth probably contained the following molecules: A) H2O, CO2, N2 , CH4, and NH3. B) H2O, CO2, CH4, C6H12O6, and NH3. C) H2O, CO2, CH4, C6H12O6, and COO-CH2NH+3. D) H2O, CO2, CH4, COOHCH2NH3, and NH3. E) none of the above Ans: A Level of Difficulty: Easy Section: 1.1.A Learning objective: The Origin of Life 3 13. In 1953, Urey and Miller carried out an experiment in which they subjected a mixture of H2O, CH4, NH3, and H2 to electrical discharges. Which of the following were among the products? A) proteins B) amino acids C) nucleic acids D) ribosomes E) all of the above Ans: B Level of Difficulty: Easy Section: 1.1.A Learning objective: The Origin of Life 14. Which of the following statements about hydrothermal vents is true? A) The vents have temperatures as high as 800°C and emit H2S and metal sulfides. B) The vents have temperatures as high as 600°C and emit H2S and metal nitrates. C) The vents have temperatures as high as 400°C and emit H2S and metal sulfides. D) none of the above E) all of the above Ans: C Level of Difficulty: Moderate Section: 1.1.A Learning objective: The Origin of Life 4 For questions 15-18, consider the structure of the coenzyme NADP B O NH 2 O O P N O A O H H OH OH O H O P H NH2 C O N N O N N D O H H OH O H H O P E O O 15. Which arrow points at a phosphate ester bond? A) A B) B C) C D) D E) E Ans: E Level of Difficulty: Easy Section: 1.1.B Learning objective: The Origin of Life 5 16. Which arrow points at an amide bond? A) A B) B C) C D) D E) E Ans: B Level of Difficulty: Easy Section: 1.1.B Learning objective: The Origin of Life 17. Which arrow points at an anhydride bond? A) A B) B C) C D) D E) E Ans: A Level of Difficulty: Moderate Section: 1.1.B Learning objective: The Origin of Life 18. Which arrow points at a glycosidic bond? A) A B) B C) C D) D E) E Ans: D Level of Difficulty: Moderate Section: 1.1.B Learning objective: The Origin of Life 6 19. Which of the following developed during the evolution of eukaryotic cells from prokaryotic cells? A) DNA B) the cell membrane C) nuclear membranes D) ribosomes E) proteins Ans: C Level of Difficulty: Easy Section: 1.2.C Learning objective: Cellular Architecture 20. Using phylogeny all living organisms can be divided into the following domains: A) bacteria, eukarya, and vertebrate B) archaea and eukarya C) bacteria, eukarya, and archaea D) eukarya and bacteria E) none of the above Ans: C Level of Difficulty: Moderate Section: 1.2.C Learning objective: Cellular Architecture 21. The theory of evolution includes which of the following principles? A) Evolution is not directed toward a specific goal. B) Evolution is ongoing, and is constrained by its past. C) Evolution requires some sloppiness for adaptation to changes. D) A and B E) A, B, and C Ans: E Level of Difficulty: Easy Section: 1.2.D Learning objective: Cellular Architecture 7 22. Which three cellular components are present in both prokaryotes and eukaryotes? A) ribosomes, chloroplasts, mitochondria B) nucleus, ribosomes, RNA C) RNA, DNA, ribosomes D) endoplasmic reticulum, DNA, RNA E) mitochondria, DNA, RNA Ans: C Level of Difficulty: Easy Section: 1.2.B Learning objective: Cellular Architecture 23. The bulk of aerobic metabolism in eukaryotic cells takes place in A) the endoplasmic reticulum. B) the nucleus. C) the mitochondria. D) peroxisomes. E) the Golgi apparatus. Ans: C Level of Difficulty: Easy Section: 1.2.B Learning objective: Cellular Architecture 24. Which cellular compartment or organelle is involved in the synthesis of proteins and lipids? A) endoplasmic reticulum B) lysosomes C) peroxisomes D) vacuoles E) all of the above Ans: A Level of Difficulty: Moderate Section: 1.2.C Learning objective: Cellular Architecture 8 25. Which of the following is a similarity between all prokaryotes and all eukaryotes? A) Both contain DNA in a nucleus. B) Both contain some of the same membrane bound cell organelles (like mitochondria, Golgi complexes, etc). C) Both have a cytoskeleton. D) All of the above are similarities between prokaryotes and eukaryotes. E) None of the above is a similarity between prokaryotes and eukaryotes. Ans: E Level of Difficulty: Easy Section: 1.2.B Learning objective: Cellular Architecture 26. Which of the following statements concerning prokaryotes is false? A) Prokaryotes are made up of two major groupings: the eubacteria and the archaea, which are as different from each other as from the eukaryotes. B) Prokaryotes are generally much smaller than the eukaryotic cells. C) Prokaryotes are one branch of the newer, more accurate phylogenic tree made up of prokarya, archaea and eukarya. D) Prokaryotes do not have organelles. E) None of the above is false. Ans: C Level of Difficulty: Easy Section: 1.2.B Learning objective: Cellular Architecture 27. Which of the following statements about eukaryotes is not true? A) They contain organelles like mitochondria, chloroplasts, the endoplasmic reticulum and the nucleus. B) They are usually 10 to 100 microns in diameter. C) They can be either unicellular or multicellular. D) They are also called archaea. E) All of the above are true of eukaryotes. Ans: D Level of Difficulty: Easy Section: 1.2.B Learning objective: Cellular Architecture 9 28. Which of the following statements about the theories of (bio)chemical evolution is not true? A) During chemical evolution, simple organic molecules (monomers) condensed to form more complex molecules (polymers) which then began to replicate based upon complementarity. B) Margulis suggested that mitochondria and chloroplasts evolved from the symbiotic relationship between primordial prokaryotic and eukaryotic cells. C) The first cells were probably formed when self-replicating systems were enveloped in membranous vesicles. D) Oparin and Haldane demonstrated that by passing an electrical discharge through a vessel containing H2O, CO2, N2, CH4 and NH3 some basic biological building blocks (like simple amino acids) could have formed abiotically in the earth’s early atmosphere. E) The RNA world hypothesis as proposed by Woese, Crick and Orgel states that RNA, instead of protein, was the first self replicating biochemical molecule that evolved because RNA could have stored genetic information and performed the catalytic roles necessary for primitive selfreplication. Ans: D Level of Difficulty: Moderate Section: 1.2.C Learning objective: Cellular Architecture 29. Which of the following statement(s) is (are) not true? A) Margulis proposed the endosymbiotic theory to explain the evolution of mitochondria and chloroplasts. B) Woese proposed the “new” phylogenic tree that divides living organisms into the 3 domains of bacteria, archaea and eukarya based upon genetic relationships rather than obvious morphological similarities. C) Urey and Miller conducted an experiment that involved sparking a mixture of NH3, CH4, H2O and H2 gases to yield amino acids, some of the fundamental building blocks of life. D) All of the above are false. E) All of the above are true. Ans: E Level of Difficulty: Easy Section: 1.2.C Learning objective: Cellular Architecture 10 30. Halophiles and thermophiles are A) early versions of eukaryotic cells. B) highly evolved organisms that thrive in their specific environments. C) relatively inefficient and unevolved organisms. D) more complex than eukaryotes. E) extremely slow growing. Ans: B Level of Difficulty: Easy Section: 1.2.B Learning objective: Cellular Architecture 31. Which of the statements about viruses is not true? A) Viruses are much simpler than cells. B) Viruses are the simplest living organisms. C) Viruses lack the necessary metabolic apparatus to reproduce. D) Viruses are dependent on host cells. E) All the statements are true. Ans: B Level of Difficulty: Easy Section: 1.2.B Learning objective: Cellular Architecture 32. Lynn Margulis’ Theory of Endosymbiosis is an explanation for the origin of A) the endoplasmic reticulum. B) the nucleus. C) the mitochondria. D) peroxisomes. E) the Golgi apparatus. Ans: C Level of Difficulty: Easy Section: 1.2.B Learning objective: Cellular Architecture 11 33. Phylogeny is A) the science of biological classification based on gross morphology. B) the science of biological classification based on the evolutionary relationships between organisms. C) the science of biological classification based on reproductive strategies. D) the branch of science that studies phyllopods. E) none of the above Ans: B Level of Difficulty: Easy Section: 1.2.B Learning objective: Cellular Architecture 34. Taxonomy is A) the science of biological classification based on gross morphology. B) the science of biological classification based on the evolutionary relationships between organisms. C) the science of biological classification based on reproductive strategies. D) the branch of science that studies taxidermy. E) none of the above Ans: A Level of Difficulty: Easy Section: 1.2.B Learning objective: Cellular Architecture 35. Which group of organisms is not prokaryotic? A) Fungi B) Archaea C) Purple bacteria D) Cyanobacteria E) Methanococcus Ans: A Level of Difficulty: Easy Section: 1.2.B Learning objective: Cellular Architecture 12 36. The term molecular weight is a term used by biochemists that refers to A) the density of a particle. B) a dimensionless quantity that is defined as the ratio of the mass of the particle to 1/12 the mass of a 12C atom. C) Daltons divided by the mass of a hydrogen atom. D) all of the above E) none of the above Ans: B Level of Difficulty: Moderate Section: 1.3.A Learning objective: Thermodynamics 37. The second law of thermodynamics states: A) that spontaneous processes are characterized by the overall conversion of order to disorder. B) that spontaneous processes are characterized by the conversion of work to force. C) that nonspontaneous processes are characterized by the conversion of order to disorder. D) that spontaneous processes are characterized by the conversion heat to pressure. E) none of the above Ans: A Level of Difficulty: Easy Section: 1.3.B Learning objective: Thermodynamics 38. Change in enthalpy (H) is best defined as A) the sum of heat absorbed and work done. B) the heat transferred at constant pressure. C) the pressure change at constant temperature. D) the measure of disorder in a system. E) none of the above Ans: B Level of Difficulty: Easy Section: 1.3.B Learning objective: Thermodynamics 13 39. If gas molecules in an enclosed chamber are allowed to enter a second chamber, the resulting redistribution of gas molecules represents an increase in A) enthalpy. B) entropy. C) force. D) chemical potential. E) all of the above Ans: B Level of Difficulty: Easy Section: 1.3.B Learning objective: Thermodynamics 40. Consider the reaction A + B  C + D. After reaching equilibrium at 25°C, the following concentrations of reactants and products were measured: [A] = 10 M, [B] = 15 M, [C] = 10 M, [D] = 10 M. Calculate G° for this reaction. A) 1000 J/mol B) 10 kJ/mol C) 1 J/mol D) insufficient data to determine answer E) none of the above Ans: A Level of Difficulty: Moderate Section: 1.3.D Learning objective: Thermodynamics 41. A reaction with a ______ H and a ______ S, will never be spontaneous. A) positive, positive B) positive, negative C) negative, positive D) negative, negative E) none of the above Ans: B Level of Difficulty: Moderate Section: 1.3.D Learning objective: Thermodynamics 14 42. An endergonic reaction with a ______ H and a ______ S can be changed into an exergonic reaction by decreasing the temperature. A) positive, positive B) positive, negative C) negative, positive D) negative, negative Ans: D Level of Difficulty: Moderate Section: 1.3.D Learning objective: Thermodynamics 43. The G° for the conversion of glucose 6-phosphate (G6P) to fructose 6-phosphate (F6P) is +1.7 kJ/mole. In a particular human cell the concentration G6P is 8.0 µM and the concentration F6P is 1.0 µM. Calculate the G of the reaction as it occurs in this cell at 37°C? A) −37 kJ/mol B) −3.7 kJ/mol C) 0 kJ/mol D) +7.1 kJ/mol E) −0.6 kJ/mol Ans: B Level of Difficulty: Moderate Section: 1.3.D Learning objective: Thermodynamics 44. For a reaction with H = 23 kJ/mol and S =22 J/K•mol, at 2°C, the reaction is: A) spontaneous B) nonspontaneous C) at equilibrium D) impossible to determine reactivity E) none of the above Ans: B Level of Difficulty: Moderate Section: 1.3.D Learning objective: Thermodynamics 15 45. Calculate the G for a reaction with H = 20. kJ/mol and S =20. J/K•mol, that is carried out at 27°C. A) 14 J/mol B) 140 J/mol C) 1400 J/mol D) 14,000 J/mol E) none of the above Ans: D Level of Difficulty: Moderate Section: 1.3.D Learning objective: Thermodynamics 46. A spontaneous process A) occurs without the addition of free energy. B) has a G<0. C) is exergonic. D) is all of the above E) is none of the above Ans: D Level of Difficulty: Easy Section: 1.3.C Learning objective: Thermodynamics 47. An increase in disorder in the system A) is required for a process to be spontaneous. B) results in a decrease in entropy. C) is characteristic of a system increasing in enthalpy. D) results in the factor TS being positive . E) is found in every exergonic process. Ans: D Level of Difficulty: Moderate Section: 1.3.B Learning objective: Thermodynamics 16 48. Living organisms A) are closed systems. B) maintain a steady state. C) exist outside the laws of thermodynamics. D) are all of the above E) are none of the above Ans: B Level of Difficulty: Easy Section: 1.3.E Learning objective: Thermodynamics 49. Enzymes accelerate biochemical reactions by A) decreasing the G for the reactions. B) increasing the G for the reactions. C) establishing a ‘closed system’ for each reaction. D) promoting reaction pathways associated with a positive G. E) providing a more favorable pathway for the reactions. Ans: E Level of Difficulty: Moderate Section: 1.3.E Learning objective: Thermodynamics 50. A van’t Hoff plot A) plots ln Keq versus T B) plots K versus –TS. C) plots Keq versus 1/T. D) is a good method to determine H° and S°. E) determines Keq by plotting H° versus 1/T. Ans: D Level of Difficulty: Moderate Section: 1.3.D Learning objective: Thermodynamics 17 51 Keq can be determined from the change in standard free energy using the equation A) Keq = e−G°/RT B) Keq = ln e−G°/TS C) Keq = e−H/RT D) Keq = e−G°/TS E) Keq = log e−G°/RT Ans: A Level of Difficulty: Easy Section: 1.3.D Learning objective: Thermodynamics 52. Living organisms are classified thermodynamically as: A) open systems. B) closed systems. C) isolated systems. D) thermally isolated. E) none of the above Ans: A Level of Difficulty: Easy Section: 1.3.D Learning objective: Thermodynamics 18