True/False Indicate whether the statement is true or false. Write + for true and 0 for false. |
| 1. | Atoms have a positive charge. |
| 2. | An element is made up of more than one kind of atom. |
| 3. | Hydrogen and oxygen atoms have an equal number of electrons. |
| 4. | A molecule is an atom that has gained or lost an electron. |
| 5. | An atom that gains or loses one or more electrons is called an ion. |
| 6. | An atom with more electrons than protons has a positive charge. |
| 7. | Ionic bonds form between two negatively charged particles. |
| 8. | A covalent bond forms between two atoms that share electrons to form a molecule. |
| 9. | Adhesion is an attraction between different substances. |
| 10. | The ability of water to retain heat helps cells maintain homeostasis. |
| 11. | Nonpolar molecules dissolve well in water. |
| 12. | Water molecules attract nonpolar molecules such as oil. |
| 13. | Organic compounds contain carbon atoms that are covalently bonded to other elements—typically hydrogen, oxygen, and other carbon atoms. |
| 14. | A nucleotide has four parts. |
| 15. | RNA is made up of a double strand of nucleotides. |
| 16. | DNA stores hereditary information that can be used to make proteins. |
| 17. | When cells break down food, the energy from the food is temporarily stored as ATP. |
| 18. | The amount of energy needed to cause a chemical reaction to start is called activation energy. |
| 19. | Without enzymes, chemical reactions necessary for life would not occur at a rate sufficient to sustain life. |
| 20. | Enzymes speed up a chemical reaction by increasing the activation energy of the reaction. |
| 21. | When an enzyme binds with its substrate, the activation energy needed for the chemical reaction to occur is increased. |
| 22. | Chemical reactions that occur in cells are called biochemical reactions. |
Multiple Choice Identify the choice that best completes the statement or answers the question. |
| 23. | Atoms are composed of a. | protons. | c. | electrons. | b. | neutrons. | d. | All of the above |
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| 24. | The electrons of an atom a. | are found in the nucleus along with the protons. | b. | occupy the space surrounding the nucleus. | c. | have a positive charge. | d. | are attached to the positive charge of neutrons. |
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| 25. | The smallest particle of matter that can retain the chemical properties of carbon is a(n) a. | carbon molecule. | c. | carbon atom. | b. | carbon macromolecule. | d. | element. |
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| 26. | A substance that is composed of only one type of atom is called a(n) a. | nucleus. | c. | element. | b. | cell. | d. | molecule. |
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| 27. | All matter is composed of a. | cells. | c. | atoms. | b. | molecules. | d. | carbon. |
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| 28. | A molecule that has a partial positive charge on one side and a partial negative charge on the other side is called a a. | nonpolar molecule. | c. | charged molecule. | b. | polar molecule. | d. | bipolar molecule. |
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| 29. | A chemical formula shows the a. | kinds of bonds found in the molecule. | b. | kinds of bonds found in the compound. | c. | kinds of elements found in the compound. | d. | arrangement of the elements found in the compound. |
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| 30. | Ionic bonds form between molecules that have a. | opposite charges. | c. | no charges. | b. | the same charge. | d. | neutral charges. |
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| 31. | The bond formed when two atoms share a pair of electrons is called a(n) a. | hydrogen bond. | c. | covalent bond. | b. | ionic bond. | d. | water bond. |
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| 32. | Sharing of electrons in the outer energy levels of two atoms a. | results in ion formation. | b. | occurs in covalent bonds. | c. | only occurs if both are atoms of the same element. | d. | is found only among carbon atoms. |
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| 33. | Water is important to life because it a. | surrounds all cells. | b. | is found inside cells. | c. | influences the shape of the cell membrane. | d. | All of the above |
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| 34. | Nonpolar molecules have a. | no negative or positive poles. | c. | only a negative pole. | b. | both negative and positive poles. | d. | only a positive pole. |
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| 35. | When placed in the same container, oil and water do not mix because a. | they are both polar. | c. | they are both nonpolar. | b. | water is polar and oil is nonpolar. | d. | water is nonpolar and oil is polar. |
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| 36. | Due to the polarity of water, compounds that dissolve best in water contain a. | nonpolar bonds. | c. | polar bonds. | b. | ionic bonds. | d. | Both (b) and (c) |
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| 37. | Water is a polar molecule because a. | it contains two hydrogen atoms for each oxygen atom. | b. | it has a charge. | c. | different parts of the molecule have slightly different charges. | d. | it does not have a charge. |
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| 38. | Acidic solutions have a pH that is a. | less than 7. | c. | a negative number. | b. | between 7 and 14. | d. | more than 7. |
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| 39. | Hydrogen ions, H+, react with hydroxide ions, OH-, to form a. | water. | c. | a base. | b. | an acid. | d. | None of the above |
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| 40. | Which of the following is not an organic macromolecule? a. | carbohydrate | c. | lipid | b. | ice | d. | nucleic acid |
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| 41. | All organic compounds contain the element a. | carbon. | c. | calcium. | b. | nitrogen. | d. | sodium. |
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| 42. | Which of the following organic molecules are classified as carbohydrates? a. | amino acids | c. | nucleotides | b. | fatty acids | d. | sugars |
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| 43. | Polysaccharides are a. | carbohydrates. | c. | proteins. | b. | lipids. | d. | unsaturated fats. |
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| 44. | Lipids are a. | polar molecules. | c. | water soluble. | b. | similar to water molecules. | d. | nonpolar molecules. |
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| 45. | Which of the following organic molecules are most closely related to proteins? a. | amino acids | c. | nucleotides | b. | fatty acids | d. | sugars |
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| 46. | Long chains of amino acids are found in a. | carbohydrates. | c. | proteins. | b. | lipids. | d. | sugars. |
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| 47. | All of the following are examples of lipids except a. | saturated fats. | c. | cholesterol. | b. | starch. | d. | earwax. |
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| 48. | Lipids are soluble in a. | water. | c. | oil. | b. | salt water. | d. | All of the above |
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| 49. | Which organic molecules below are most closely related to lipids? a. | amino acids | c. | nucleotides | b. | fatty acids | d. | sugars |
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| 50. | Which of the following organic molecules are most closely related to nucleic acids? a. | amino acids | c. | nucleotides | b. | fatty acids | d. | sugars |
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| 51. | Which of the following is a carbohydrate? a. | DNA | c. | wax | b. | insulin | d. | sucrose |
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| 52. | Carbohydrates and lipids have many carbon-hydrogen bonds; therefore, they both a. | store energy in these bonds. | c. | dissolve only in vinegar. | b. | are easily dissolved in water. | d. | exist only in cells of plants. |
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| 53. | Refer to the illustration above. Molecules like Molecule B are found in a. | carbohydrates. | c. | nucleic acids. | b. | lipids. | d. | proteins. |
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| 54. | Liquid fats called oils contain a. | mostly unsaturated fatty acids. | c. | many glucose molecules. | b. | mostly saturated fatty acids. | d. | amino acids. |
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| 55. | Animals store glucose in the form of a. | cellulose. | c. | wax. | b. | glycogen. | d. | lipids. |
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| 56. | The shape of a protein is primarily determined by a. | the type and sequence of its amino acids. | b. | its size. | c. | its cell location. | d. | None of the above |
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| 57. | The two types of nucleic acids are a. | chlorophyll and retinal. | c. | lipids and sugars. | b. | DNA and RNA. | d. | glucose and glycogen. |
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| 58. | DNA stores a. | fat. | c. | protein. | b. | carbohydrates. | d. | heredity information. |
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| 59. | The two strands of a DNA molecule are held together by a. | ionic bonds. | c. | hydrogen bonds. | b. | covalent bonds. | d. | None of the above |
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| 60. | A molecule shaped like a spiral staircase (double helix) is typical of a. | deoxyribonucleic acid. | c. | lipids. | b. | ribonucleic acid. | d. | carbohydrates. |
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| 61. | ATP (adenosine triphosphate) stores energy for cells to use in the bonds between its a. | amino acids. | c. | nucleotides. | b. | carbon atoms. | d. | phosphates. |
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| 62. | Refer to the illustration above. Which graph illustrates what happens during an energy-releasing reaction? a. | Graph A | b. | Graph B | c. | both graphs because they each show a different stage of an energy releasing reaction | d. | None of the above |
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| 63. | Refer to the illustration above. Which graph illustrates a reaction during which energy is released? a. | Graph A | b. | Graph B | c. | both graphs because all chemical reactions release energy | d. | None of the above |
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| 64. | Refer to the illustration above. Which of the following statements regarding the graph is true? a. | Reaction 2 occurs faster than Reaction 3 because Reaction 2 requires more energy than Reaction 3. | b. | The difference between the graphs shown for Reaction 2 and Reaction 3 is because of a difference in the activation energy of these reactions. | c. | Reactant A contains more energy at the beginning of the reaction than product C has after the reaction. | d. | All of the above |
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| 65. | Refer to the illustration above. Reaction 3 in the graph a. | probably occurred in the presence of a catalyst. | b. | requires more activation energy than Reaction 2. | c. | is the same as Reaction 1, but faster. | d. | is slower than Reaction 2. |
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| 66. | The molecule on which an enzyme acts is called a(n) a. | active site. | c. | organic molecule. | b. | inactive site. | d. | substrate. |
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| 67. | An enzyme a. | is not used up when catalyzing a reaction. | b. | lowers the activation energy of a reaction. | c. | bonds with a substrate molecule at the enzyme’s active site. | d. | All of the above |
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| 68. | Which of the following conditions affects the function of enzymes? a. | pH | c. | enzyme concentration | b. | heat | d. | All of the above |
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| 69. | Reducing activation energy a. | is a violation of the laws of nature. | b. | requires higher temperatures than those found within cells. | c. | occurs only when reactants are quickly added to the reaction mixture. | d. | is accomplished by the action of catalysts on reactants. |
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| 70. | Enzymes a. | are able to heat up molecules so that they can react. | b. | always provide carbon dioxide for chemical reactions. | c. | are biological catalysts. | d. | absorb excess heat so that reactions occur at low temperatures. |
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| 71. | A cell contains a. | thousands of different kinds of enzymes, each promoting a different chemical reaction. | b. | one kind of enzyme that promotes thousands of different chemical reactions. | c. | approximately 100 kinds of enzymes, each promoting a different chemical reaction. | d. | one enzyme that promotes photosynthesis and one enzyme that promotes cellular respiration. |
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| 72. | Amylase is a digestive enzyme that breaks down starch into a. | amino acids. | c. | glycogen. | b. | glucose. | d. | cellulose. |
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| 73. | The digestive enzyme pepsin works with hydrochloric acid to break down proteins in the stomach. Pepsin probably works best at a pH of a. | 11. | c. | 3. | b. | 7. | d. | Both (b) and (c). |
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