Cell Biology Practice Multiple Choice Exam 1

Answer Key 1 C 2 E 3 E 4 A 5 B 6 B 7 C 8 B 9 D 10 D 11 C 12 D 13 C 14 A 15 B 16 B 17 A 18 D 19 A 20 D 21 D 22 E 23 B 24 A 25 C 26 C 27 D 28 B 29 B 30 E 31 D 32 E 33 A 34 C 35 B 36 C 37 C 38 B 39 A 40 E Choose the BEST answer to the following questions: 1. The simplest level of biological organization at which something can considered “Life” is? a. atoms b. molecules c. cells d. tissues e. ecosystems 2. The main purpose of any single experiment is to a. explain an observation. b. prove unambiguously that a particular hypothesis is correct. c. give know-it-all college professors something to do. d. answer as many key questions as possible. e. test a prediction that is based on a hypothesis. 3. Metabolism is a. the consumption of energy only. b. the release of energy only. c.. the exchange of nutrients and waste products with the environment. d. the production of heat by chemical reactions. e. all conversions of matter and energy taking place in an organism 4. The part of the atom that carries a positive charge is the a. proton. b. electron. c. neutron. d. megatron. e. nucleus. 5. The atomic number of an element is the same as the number of _______ in each atom. a. neutrons b. protons c. protons plus electrons d. neutrons plus protons e. neutrons plus electrons 6. An atom with additional neutrons has a larger atomic mass and can undergo radioactive decay. They are known as? a. chaperones b. isotopes. c. variants d. isoforms e. none of the above are correct 7. The element Nitrogen is found in the second row of the periodic table and has an atomic number of 7. How many electrons must Nitrogen gain in order for its valence shell to be full? a. 0 b. 2 c. 3 d. 7 e. 8 8. Which of the following bonds is formed when atoms share electrons unequally? a. non-polar covalent b. polar covalent c. cationic d. anionic e. van der waals force 9. Which of the following are special properties of water? a. It has a high (large) heat capacity. b. Its molecules form hydrogen bonds with themselves and solutes. c. It dissolves all four classes of biological molecules (nucleic acids, proteins, lipids, and carbohydrates). d. Answers A and B are correct e. All of the above are correct 10. How would you make 1 liter of an aqueous solution with a 0.5 M concentration of a compound that has a molecular weight of 200 daltons (grams)? a. Add 0.20 grams of the compound to 1000 ml of water. b. Add 200 grams of the compound to 1000 ml of water. c. Measure out 200 grams of the compound and add water until the volume equals 1000 ml. d. Measure out 100 grams of the compound and add water until the volume equals 1000 ml. e. Measure out 0.5 grams of the compound and add water until the volume equals 1000 ml. 11. Assuming you have made the solution preceding question correctly, how many molecules of the compound are in the 1 liter of solution? a. 0.5 b. 100 c. 3.011 x 1023 d. 200 e. cannot be determined from information given 12. A soft drink may have an H+ concentration of 10–3 mol/L. The pH of this drink is? a. 0.001. b. –3. c. 0. d. 3. e. 1,000. 13. Carbonic acid and sodium bicarbonate act as buffers in the blood. When a small amount of acid is added to this buffer, more H+ ions combine with the bicarbonate ions. When this happens, the pH of the blood? a. becomes significantly more basic. b. becomes significantly more acidic. c. does not significantly change. d. Answers A and B are correct. e. All of the above are correct. 14. Which of the following functional groups is a weak acid? a. carboxyl b. amino. c. hydroxyl. d. phosphate. e. ketone. 15. Which statements regarding a 2-carbon molecule with an amino functional group is/are TRUE? a. It is a weak acid b. It is a weak base. c. It is non-charged and non-polar. d. It will be hydrophobic e. All of the above are true 16. Which of the following is a correct monomer/polymer pairing? a. Monosaccharide/phospholipid b. Amino acid/protein c. Triglyceride/cellulose d. Nucleotide/steroid e. Monosaccharide/DNA 17. During a condensation reaction in which two monosaccharides are joined to form a disaccharide, a(n) ___?____ bond is formed. a. glyosidic bond b. peptide bond c. phosphodiester bond d. answers A and B are correct e. all of above are correct 18. Which of the following can have enzymatic activity? a. RNA. b. proteins. c. carbohydrates d. answer A and B are correct e. all of the above are correct 19. Which of the following amino acid(s) is unique in that it does NOT contain a central chiral carbon? a. Glycine b. Tyrosine c. Lysine d. Cysteine e. Threonine 20. Which of the following amino acids is non-polar and non-charged? a. Cysteine b. Tyrosine c. Lysine d. Valine e. Threonine 21. Which of the following elements is not normally found in any of the 20 amino acids? a. carbon b. nitrogen c. sulfur d. phosphorus (phosphate) e. hydrogen 22. Which of the following statements about proteins is/are FALSE? a. They possess peptide bonds between amino acids. b. They can form structural components of the cell. c. They can be enzymes. d. They can be signaling molecules (hormones) such as insulin. e. They can be genetic material. 23. The “C” terminus of a polypeptide is? a. The first amino acid in a polypeptide. b. The last amino acid in a polypeptide. c. An amino acid with a free “R” group. d. An amino acid with a free amino group. e. None of the above are correct. 24. The sequence of amino acids incorporated into a polypeptide is which level of protein structure/folding? a. primary b. secondary c. tertiary d. quaternary. e. none of the above are correct. 25. The formation of alpha-helices and beta-sheets in proteins is primarily stabilized by? a. ionic bonds b. covalent bonds c. hydrogen bonds d. disulfide bonds e. hydrophobic interactions 26. A type of protein that functions by helping other proteins fold correctly is called a a. foldzyme. b. renaturing protein. c. chaperone protein. d. hemoglobin. e. denaturing protein. 27. L-amino acids and D-amino acids differ from each other in what manner? a. they are enantiomers of each other b. L-amino acids are biologically active, D-amino acids are not c. D-amino acids are more hydrophobic than L-amino acids d. answers A and B are correct e. all of the above are correct 28. Which of the following has the molecular formula of C6H12O6? a. an amino acid. b. monosaccharide. c. triglyceride. d. a fatty acid. e. none of the above 29. The difference between α- and β-glucose is a. in the number of covalent bonds present. b. in the arrangement of OH and H atoms attached to the carbon at position 1. c. in the type of R group attached to the terminal carbon. d. that α-glucose is polar, whereas β-glucose is nonpolar. e. that α-glucose is a pentose, whereas β-glucose is a hexose. 30. A phospholipid contains which of the following? a. glycerol. b. a polar head group c. 2 fatty acid sides chains d. answers A and B are correct e. all of the above are correct 31. Polyunsaturated triglycerides differ from saturated triglycerides in that they? a. have a lower melting temperature b. have more carbon to carbon double bonds. c. are more often found in animal fats than in plant oils. d. answers A and B are both correct e. all of the above are correct 32. Which statement(s) regarding purines and pyrimidines is/are TRUE? a. Purines only have single bonds in their structure, whereas pyrimidines have both single and double bonds in their structure. b. Pyrimidines are found in RNA only; while purines are found in DNA only. c. Purines consist of hydrogen, carbon, oxygen, and nitrogen, whereas pyrimidines have phosphorus, hydrogen, carbon, oxygen, and nitrogen. d. Purines include the bases of guanine and cytosine; pyrimidines include the bases of adenine and thymine. e. Purine bases are double-ring structures, whereas pyrimidine bases are single-ring structures. 33. Which of the following would NOT be found in DNA? a. ribose. b. phosphate c. cytosine d. guanine e. thymine 34. What is attached to the 3´-carbon of deoxyribose in DNA? a. Adenine b. Phosphate c. Hydroxyl d. Thymine e. Hydrogen 35. What is the nucleotide sequence of the complementary strand of the DNA molecule: 5’- T T A C G C T-3’? a. 5’-T T A C G C T-3’ b. 3’-A A T G C G A-5’ c. 3’-G G C A T A G-5’ d. 5’-C C G T T A T-3’ e. 3’-A G C G T A A-5’ 36. A guanine/cytosine base paring in DNA is held together with which type of bonds? a. peptide b. van der waals c. hydrogen d. ionic e. glycosidic 37. The central dogma of molecular biology states that a. the information flow in a cell is from DNA to a protein to RNA. b. the information flow between DNA, RNA, and a protein is reversible. c. the information flow in a cell is from DNA to RNA to protein. d. the information flow in a cell is from protein to RNA to DNA. e. the genetic code is ambiguous. 38. All life we can imagine needs? a. oxygen b. water. c. carbon dioxide d. sunlight e. methane 39. Examination of meteorites suggests that a. biological molecules are not limited to Earth. b. early cellular life was commonly obliterated by meteorite impact. c. comets brought Earth most of its water. d. meteorites brought life to Earth. e. meteorites are responsible for Earth’s magnetic field. 40. Which of the following have been demonstrated experimentally? a. RNA-like molecules can self-replicate, elongate, and mutate b. Basic metabolic reactions can occur spontaneously if energy, chemical substrates, and inorganic catalysts are present c. Complex organic molecules can originate from inorganic ones if heat and electricity are applied d. Answers A and B are correct e. All of the above are correct