ZOOL. 251 EXAM QUESTIONS - CHEMISTRY

[1-9] [10-19] [20-29] [30-39] [40-49] [50-59] [60-69] [70-79] [80-89] [90-99] [100-109]

[BATCH 973]

[BATCH 981]

[BATCH 941]

[BATCH 963]

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BATCH 973

1-9

1. When ionic bonds are formed, the atom that loses or donates an electron, and thus gains a positive charge, is termed:
   1. covalent
   2. anion
   3. cation
   4. isotope
   5. none of the above [top]

2. The atomic number conveys what two useful pieces of information about an atom?
   1. # of protons and neutrons
   2. # of electrons and neutrons
   3. # of protons and electrons
   4. # of neutrons and cations
   5. # of electrons and isotopes [top]

3. Variants of an element with the same atomic number but different mass numbers are:
   1. compounds
   2. anions
   3. cations
   4. isotopes
   5. none of the above [top]

4. A chemical bond in which electrons are lost or gained by the atoms involved is what type of bond?
   1. hydrogen
   2. ionic
   3. electrostatic
   4. covalent
   5. none of the above [top]

5. A term used to refer to the total solute concentration of a solution, independent of molecular weight or charge, is:
   1. molarity
   2. osmolarity
   3. degree of dissociation
   4. solubility
   5. none of the above[top]

6. Which of the following is most correct regarding expression of concentration?
   1. the atomic number of the solute is needed to calculate molarity
   2. percent solutions reflect the # of parts/1000 ml
   3. the atomic weight of the solvent must be known to calculate molarity
   4. the molarity reflects the number of moles of solute per 1000 ml of solution
   5. none of the above [top]

7. Which of the following best describes a phospholipid molecule?
   1. hydrophobic
   2. neutral
   3. hydrophilic
   4. 1 and 3
   5. 1, 2 and 3 [top]

8. The hydrogen ion concentration (moles/liter) of a solution with a pH of 6 is:
   1. 6.0 M
   2. 10^-6 M
   3. 0.6 M
   4. 10^-8 M
   5. none of the above [top]

9. The importance of solutions of weak acids, such as H₂CO_3, in buffering changes in plasma pH, reflect which physical characteristic?
   1. dissociation is incomplete
   2. dissociation is pH-dependent
   3. dissociation is reversible
   4. all of the above
   5. none of the above [top] [1-9]

10-19

10. In animal cells, carbohydrates are primarily stored as:
    1. steroids
    2. starch
    3. glycogen
    4. fat
    5. none of the above [top]

11. In biological systems, carbohydrates have a structural/functional role in association with which of the following?
    1. lipids
    2. RNA
    3. protein
    4. all of the above
    5. none of the above [top]

12. The primary components of a triglyceride include:
    1. three glycerol molecules
    2. glycerol and fatty acids
    3. glycerol and nucleic acids
    4. glycerol and amino acids
    5. none of the above [top]

13. Of the five major types of lipids, which are most important as constituents of cell membranes?
    1. triglycerides and prostaglandins
    2. eicosanoids and steroids
    3. steroids and phospholipids
    4. fatty acids and triglycerides
    5. none of the above [top]

14. A linear, H₂O-insoluble molecule that is highly stable is what type of protein?
    1. fibrous
    2. globular
    3. an enzyme
    4. all of the above
    5. none of the above [top]

15. Amino acids contain atoms of which elements?
    1. N, C, O, H
    2. C, H, P, N
    3. H, C, O
    4. C, Cl, N, H
    5. none of the above [top]

16. Osmosis is unique from diffusion, because osmosis is limited to the passage of which of the following across the cell membrane?
    1. electrolytes
    2. ions
    3. H₂O
    4. proteins
    5. none of the above [top]

17. Which is not true of proteins?
    1. may be denatured by heat or acidity
    2. some function as enzymes
    3. serve as molecular carriers of hereditary information
    4. function depends upon three-dimensional shape
    5. none of the above [top]

18. A complex molecule made-up of simple sugars is a:
    1. monosaccharide
    2. nucleic acid
    3. polysaccharide
    4. disaccharide
    5. sweet [top]

19. A red blood cell placed in pure water (hypotonic) would:
    1. shrink
    2. swell and burst
    3. would not change
    4. swell initially and then shrink
    5. none of the above [top] [10-19]

20-29

20. At a physiological pH of 7.4, what is the relationship between [H⁺] and [OH^-]?
    1. [H⁺] = [OH^-]
    2. [H⁺] < [OH^-]
    3. [H⁺] > [OH^-]
    4. there are no H⁺ ions at that pH
    5. none of the above [top]

21. Important functions of carbohydrates include which of the following?
    1. cell recognition
    2. fuel source
    3. structural molecule
    4. all of the above
    5. none of the above [top]

22. The principle driving force behind simple diffusion is:
    1. chemical energy
    2. pressure
    3. concentration
    4. gravity
    5. none of the above [top]

23. Peptides and proteins are made of:
    1. monosaccharides
    2. fatty acids
    3. nucleic acids
    4. amino acids
    5. none of the above [top]

24. An organic compound containing C, H, O and N would most likely be a:
    1. amino acid
    2. lipid
    3. carbohydrate
    4. nucleic acid
    5. none of the above [top]

25. Defne mole. [top]

26. Which of the following is most correct regarding chemical concentration?
    1. the atomic number of the solute is needed to calculate molarity
    2. percent solutions reflect the # of parts/1000 ml
    3. the atomic weight of the solvent must be known to calculate molarity
    4. the molarity reflects the number of moles of solute per 1000 ml of solution
    5. none of the above [top]

BATCH 981

27. Isotopes of an element differ from each other in the number of:
    1. protons and electrons in the nucleus
    2. electrons in the outer energy levels
    3. neutrons in the nucleus
    4. ions in the nucleus
    5. protons in the nucleus[top]

28. The atomic number for calcium is 20. How many of the different subatomic particles are present in this atom? #protons #neutrons #electrons
    1. 10 10 10
    2. 20 10 20
    3. 20 20 10
    4. 5 15 5
    5. 20 20 20[top]

29. Listed below are the number of protons in different elements. Which would be chemically stable (i.e., inert)?
    1. 3 protons
    2. 6 protons
    3. 8 protons
    4. 10 protons
    5. 17 protons [top] [20-29]

30-39

30. Ions with a positive charge are called:
    1. cations
    2. radicals
    3. anions
    4. acidic
    5. basic [top]

31. If a pair of electrons is unequally shared between two atoms, a _______________occurs.
    1. nonpolar covalent bond
    2. double covalent bond
    3. triple covalent bone
    4. polar covalent bond
    5. hydrogen bond [top]

32. All of the following are true concerning enzymes, EXCEPT:
    1. they are usually proteins
    2. they speed up chemical reactions
    3. they increase the rate of reaction without being consumed in the process
    4. they cause reactions to occur that otherwise would not occur
    5. they act as catalysts [top]

33. In an exergonic reaction:
    1. more complex structures are produced
    2. energy is released
    3. energy is required
    4. small molecules are assembled into larger ones
    5. energy may be required [top]

34. One mole of any element:
    1. has the same mass
    2. has the same weight
    3. has the same number of atoms
    4. has the same number of electrons
    5. all of the above [top]

35. All of the following are organic compounds EXCEPT for:
    1. water
    2. carbohydrates
    3. lipids
    4. proteins
    5. nucleic acids [top]

36. The pH of your spinal fluid is 10 times more acidic than the fluid in your small intestine. If the pH of your small intestine is 8, the pH of your spinal fluid is:
    1. 80
    2. 18
    3. 7
    4. 9
    5. 0.8 [top]

37. This chemical structure is what type of molecule? H-C-C=C=C-C-C-COOH
    1. carbohydrate
    2. lipid
    3. high-energy compound
    4. protein
    5. nucleic acid [top]

38. A(n)_________ is a solute that dissociates in solution to release hydrogen ions (H+), and a(n)_________ is a solute that removes hydrogen ions from solution.
    1. base, acid
    2. acid, salt
    3. salt, base
    4. acid, base
    5. base, buffer [top]

39. All of the following are true of carbon dioxide (CO₂) EXCEPT:
    1. it is a waste product of cellular metabolism
    2. it is necessary to break down glucose
    3. it influences the rate of breathing
    4. it reacts with water in the body to form an acid
    5. it is an inorganic compound [top] [30-39]

40-49

40. Which organic molecule is INCORRECTLY matched with a function?
    1. carbohydrates -- immediate energy source for cells
    2. nucleic acids -- the genetic material
    3. RNA -- protein synthesis
    4. proteins -- hormones
    5. lipids -- hormones [top]

41. Placing a red blood cell in which solution would cause the cell to swell up?
    1. concentrated NaCl
    2. weakly concentrated NaCl, but still more concentrated than the cell itself
    3. concentrated glucose
    4. a solution with the same amount of NaCl as the cell has
    5. distilled water [top]

42. Soluble inorganic molecules whose ions will conduct an electrical current in solution are called:
    1. salts
    2. electrolytes
    3. hydrophilic
    4. buffers
    5. colloidal [top]

BATCH 941

43. What is the major cation in extracellular fluid?
    1. Na
    2. K
    3. Ca
    4. Mg
    5. proteins [top]

44. What is the major cation inside of cells?
    1. Na
    2. K
    3. Ca
    4. Mg
    5. proteins [top]

45. What is/are the anion(s) inside the cell which act(s) as the counterpart to Cl in the extracellular fluid?
    1. HCO₃
    2. HPO₄
    3. K
    4. protein
    5. B and D [top]

BATCH 963

46. Which is the simplest combination of atoms held together by chemical bonds?
    1. matter
    2. elements
    3. molecules
    4. atoms [top]

47. An atom of gold differs from an atom of lead by...
    1. the mass of each of the neutrons, protons, and electrons
    2. the shape of the neutrons, protons, and electrons
    3. the location of the neutrons, protons, and electrons with in the atom
    4. the number of neutrons, protons, and electrons
    5. all of these are correct [top]

48. Which of the following is found in the nucleus of an atom?
    1. neutrons
    2. protons
    3. electrons
    4. both a and b
    5. both b and c [top]

49. A form of carbon has an atomic number of 6 (₆C) and a mass number of 14 (¹⁴C). How many protons does this form of carbon have?
    1. 6
    2. 8
    3. 10
    4. 12
    5. 14 [top] [40-49]

50-59

50. How many neutrons does this form of carbon have?
    1. 6
    2. 8
    3. 10
    4. 12
    5. 14 [top]

51. Isotopes of the same element differ in the number of:
    1. electrons.
    2. protons.
    3. neutrons.
    4. they have the same number of all three of these subatomic particles.
    5. all three of these subatomic particles are different in an isotope. [top]

52. Which of the following atoms is reactive?
    1. an atom with 2 electrons
    2. an atom with 8 electrons
    3. an atom with 10 electrons
    4. both a and b would be reactive
    5. both a and c would be reactive [top]

53. Which of the following chemical bonds is the weakest?
    1. covalent
    2. ionic
    3. hydrogen
    4. a and b are equally weak
    5. none of these bond types are weak [top]

54. Electrical energy is:
    1. energy stored in the bonds of a chemical.
    2. energy directly involved in moving matter.
    3. the movement of charged particles.
    4. energy that travels in waves. [top]

55. Which of the following statements about energy is true?
    1. energy can be consumed.
    2. energy can be created.
    3. energy can be converted from one form to another.
    4. the amount of energy in the universe is constantly increasing. [top]

56. Anabolism is an example of a...
    1. decomposition reaction
    2. synthesis reaction
    3. exchange reaction [top]

57. Water is important biologically because once a temperature is reached it changes temperature slowly. This is refered to as having.....
    1. high heat capacity
    2. high heat of vaporization
    3. polarity
    4. reactivity [top]

58. Polar molecules readily interact with water. They are said to be.....
    1. hydrophobic
    2. hydrophilic
    3. reactive
    4. ionic [top]

59. Which of the following pH values would indicate a normal blood pH?
    1. pH of 3
    2. pH of 12
    3. pH of 7.3
    4. pH of 7.4
    5. pH of 7.6 [top] [50-59]

60-69

60. Which statement is true of pH buffers?
    1. They release hydrogen ions
    2. They accept hydrogen ions
    3. They can release or accept hydrogen ions [top]

61. Table sugar (sucrose) is made by bonding together a glucose and a fructose. Sucrose is an example of a:
    1. polysaccharide
    2. monosaccharide
    3. disaccharide [top]

62. Eicosanoids are examples of...
    1. lipids
    2. carbohydrates
    3. proteins [top]

63. Amino acids are the building blocks of....
    1. lipids
    2. carbohydrates
    3. proteins [top]

64. In the construction of an enzyme, if the non-protein component is derived from a vitamin, it is called a...
    1. holoenzyme
    2. apoenzyme
    3. coenzyme
    4. cofactor [top]

65. Which of the following is never found in RNA?
    1. adenine
    2. thymine
    3. guanine
    4. cytosine
    5. uracil [top]

66. A phospholipid is:
    1. partially hydrophilic and partially hydrophobic.
    2. hydrophobic.
    3. hydrophilic.
    4. neither hydrophilic nor hydrophobic. [top]

67. The plasma membrane (cell membrane) is:
    1. a single layered membrane that surrounds the nucleus of the cell.
    2. a double layer of protein enclosing the plasma.
    3. a phospholipid bilayer surrounding the cell.
    4. a membrane composed of tiny shelves or cristae. [top]

68. The plasma membrane is important for which of the following reasons?
    1. It is selectively permeable.
    2. It contains the cell contents.
    3. It acts as a site of cell-to-cell interaction and recognition.
    4. All of these are correct. [top]

69. Which structures are fingerlike projections that greatly increase the absorbing surface of cells?
    1. stereocilia
    2. microvilli
    3. cilia
    4. flagella [top] [60-69]

70-79

70. Cell junction which allows a cell to directly communicate with the surrounding cells is called.....
    1. gap junctions.
    2. desmosomes.
    3. peroxisomes.
    4. tight junctions. [top]

71. Cell junction which "water proofs" the cell, preventing molecules like water from passing between cells, is called.....
    1. gap junctions.
    2. desmosomes.
    3. peroxisomes.
    4. tight junctions. [top]

72. Which of the following is a function of a plasma membrane protein?
    1. circulating antibody
    2. transport channel or pore
    3. forms a lipid bilayer
    4. oxygen transport [top]

73. Passive membrane transport processes include:
    1. movement of a substance down its concentration gradient.
    2. movement of water from an area of low concentration to an area of high concentration.
    3. consumption of ATP.
    4. the use of transport proteins when moving substances from areas of low to high concentration. [top]

74. Mitochondria:
    1. are usually found in higher numbers in metabolically inactive cells.
    2. are single membrane structures involved in the breakdown of ATP.
    3. contain some of the DNA necessary for their own construction.
    4. synthesize proteins for use outside the cell. [top]

75. Ribosomes, endoplasmic reticulum, and Golgi apparatus functionally act in sequence to synthesize and modify proteins for secretory use (export) only, never for use by the cell. This statement is:
    1. false; proteins thus manufactured are for use inside the cell only.
    2. false; integral cell membrane proteins are also synthesized this way.
    3. false; lipids, not proteins, are synthesized this way. [top]
    4. true.

76. Peroxisomes:
    1. also called microbodies, contain acid and proteases.
    2. are able to remove free radicals by enzymatic action.
    3. function to digest particles ingested by endocytosis.
    4. sometimes function as secretory vesicles. [top]

77. Which of the following is true about the cell?
    1. extracellular sodium levels are high.
    2. cells are more permeable to Na+ than K+.
    3. the inside of the cell is positive relative to its outside.
    4. a and b are correct
    5. all are correct [top]

78. The main component of the cytosol is:
    1. proteins.
    2. sugars.
    3. salts.
    4. water. [top]

79. Lysosomes:
    1. are used mainly for the cell to "commit suicide."
    2. contain acid hydrolases (digestive enzymes) which are potentially dangerous to the cell.
    3. maintain a highly alkaline internal environment.
    4. are the major site of protein synthesis. [top] [70-79]

80-89

80. The nucleotides of both RNA and DNA contain a pentose (five carbon sugar). Between RNA and DNA, which one would have the heaviest (most massive) pentose? [HINT: Remember that all atoms have mass.]
    1. RNA
    2. DNA [top]

81. DNA is a double-stranded molecule held together by bonds between complementary base pairs (remember the bases are part of the nucleotides). Which of the following depicts complementary bases?

1. A-T
2. A-G
3. C-G
4. both a and b are correct.
5. both a and c are correct. [top]

82. Which of the following structures is surrounded by a phospholipid bilayer?
    1. mitochondria
    2. cell surface
    3. Golgi body
    4. both a and b
    5. all of the above [top]

83. Which of the following molecules is added to the cell plasma membrane to increase its rigidity?
    1. phospholipids
    2. glycolipids
    3. proteins
    4. cholesterol [top]

84. Which of the following proteins are present in microvilli?
    1. actin
    2. tubulin
    3. microtubules
    4. intermediate fibers [top]

85. Which of the following forms of passive transport requires a gradient (concentration or pressure) to occur?
    1. simple diffusion
    2. facilitated diffusion
    3. filtration
    4. all of the above
    5. none of the above [top]

86. The two strands of the DNA double helix are held together by:
    1. covalent bonds.
    2. ionic bonds.
    3. hydrogen bonds.
    4. peptide bonds. [top]

87. Select the most correct statement regarding the glycocalyx.
    1. It involves highly specific biological markers on the surface of the cell.
    2. It is made of carbohydrates on the surface of the cell.
    3. It is involved in some types of tissue rejection after a transplant.
    4. All of these are correct. [top]

88. Which of the following originates from the centrioles or centrosome?
    1. microtubules
    2. microfilaments
    3. intermediate filaments
    4. actin fibers [top]

89. Which of the following are constructed of microtubules?
    1. desmosomes
    2. flagella
    3. cilia
    4. a and b
    5. b and c [top] [80-89]

90-99

90. The terminal web is constructed from:
    1. microfilaments
    2. intermediate filaments
    3. microtubules [top]

91. A spherical cluster of eight histone proteins with the DNA that winds around then is called a ....
    1. chromosome
    2. chromatin
    3. nucleosome
    4. nucleoli [top]

92. Which of the following are associated with cell desmosomes and form intracellular guy wires?
    1. mircotubules
    2. microfilaments
    3. intermediate filaments
    4. actin fibers[top]

Match the following period (phase) of the cell cycle:

99. This population of cells spends its life in Go.
    1. static cells
    2. stable cells
    3. renewing cells [top] [90-99]

100-109

100. This population of cells never enters the Go phase (period) of the cell cycle.
     1. static cells
     2. stable cells
     3. renewing cells [top]

101. Which of the following nucleotides is a purine?
     1. uracil
     2. thymine
     3. cytosine
     4. guanine [top]

102. Which of the following nucleotides is found only in RNA?
     1. uracil
     2. thymine
     3. cytosine
     4. guanine [top]

103. DNA contains the instructiona for directly constructing:
     1. lipids
     2. carbohydrates
     3. proteins
     4. nucleotides [top] [100-109]