exam1-CHM438-S09-answers

exam1-CHM438-S09-answers - CHM 438/ BIO 438 Exam 1,...

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1 CHM 438/ BIO 438 Exam 1, February 11, 2009 10-10.50am Name_____________________________________ There are 20 multiple choice questions worth 3 points each and 10 short answer questions and/or calculations worth 40 points (#24-26,28,30-4points, #22,23,27,29- 5points). There are 100 total points on this exam. Multiple choice questions, please circle the best answer. Short answer questions-be concise and clear. Calculation questions-show your work. Your score: 1. A major change occurring in the evolution of eukaryotes from prokaryotes was the development of: A) DNA. B) photosynthetic capability. C) plasma membranes. D) ribosomes. E) the nucleus. Answer: E 2. 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. Answer: A 3. The chirality of an amino acid results from the fact that its α-carbon: A) has no net charge. B) is a carboxylic acid. C) is bonded to four different chemical groups. D) is in the L absolute configuration in naturally occurring proteins. E) is symmetric.
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Answer: C 4. Osmosis is movement of a: A) charged solute molecule (ion) across a membrane. B) gas molecule across a membrane. C) nonpolar solute molecule across a membrane. D) polar solute molecule across a membrane. E) water molecule across a membrane. Answer: E 5. 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 Answer: B 6. The pH of a solution of 1 M HCl is: A) 0 B) 0.1 C) 1 D) 10 E) –1 Answer: A 7. Two amino acids of the standard 20 contain sulfur atoms. They are: A) cysteine and serine. B) cysteine and threonine. C) methionine and cysteine D) methionine and serine E) threonine and serine. Answer: C 8. 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 Answer: A 9. 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)
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exam1-CHM438-S09-answers - CHM 438/ BIO 438 Exam 1,...

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