STUDY GUIDE FOR CELLS TEST
True/False
____ 1. An element is a pure substance that cannot be broken down into other substances by physical or chemical means.
____ 2. If a neutral atom contains 18 protons, it also contains 18 electrons.
____ 3. Van der Waals forces are attractive forces between molecules.
____ 4. When an endothermic chemical reaction takes place, heat is released into the environment.
____ 5. A substrate binds to an enzyme’s active site.
____ 6. In a molecule of water, the electrons are more strongly attracted to the hydrogen nuclei than to the oxygen nucleus. Therefore electrons spend more time near the hydrogen nuclei and there is an unequal sharing of electrons.
____ 7. During the light-independent reactions of photosynthesis, light energy is used to split water molecules generating protons and oxygen molecules.
____ 8. In the first step of the Calvin cycle called carbon fixation, three carbon dioxide molecules combine with six 5-carbon compounds to form twelve 3-carbon molecules called 3-phosphoglycerate.
____ 9. Glycolysis generates two ATP and two pyruvate. Only a small amount of the energy from the glucose is contained in the pyruvate.
____ 10. Alcohol fermentation is similar to lactic-acid fermentation in that NADH donates electrons during this reaction and NAD+ is regenerated.
Multiple Choice
____ 11. ____ represents a formula for a chemical compound.
a. / H / c. / Pb. / C / d. / H2O
____ 12. An atom of fluorine has nine electrons. Its second energy level has ____.
a. / two electrons / c. / seven electronsb. / eight electrons / d. / nine electrons
____ 13. Which of the atoms pictured in Figure 6-1 is most likely to form an ion?
Figure 6-1
a. / Cb. / Na
c. / O
d. / they are all equally likely to form an ion
____ 17. In the periodic table of the elements, elements in Group 1 have how many outer electrons?
a. / 0 / c. / 4b. / 1 / d. / 8
____ 18. One isotope of carbon differs from another in which way?
a. / atomic number / c. / number of neutronsb. / number of electrons / d. / number of protons
____ 19. Two substances are combined and heat is produced. Does this provide evidence that a chemical reaction took place?
a. / No, because heat is not a chemical.b. / No, because this would be a physical change.
c. / Yes, because energy is absorbed.
d. / Yes, because energy is released.
Figure 6-3
____ 20. Consider the energy diagram for a chemical reaction in Figure 6-3. Overall, is energy released or absorbed?
a. / absorbed, because the energy level increases during the reactionb. / absorbed, because the energy level of the products is greater than that of the reactants
c. / released, because the reaction is initiated by the addition of heat
d. / released because the energy level of the reactants is greater than that of the products
____ 21. A spontaneous chemical reaction occurs more rapidly when the reactants are held at 35ºC rather than 25ºC. Why would this be the case?
a. / The activation energy would be lower.b. / The activation energy would be higher.
c. / The net energy release would be lower.
d. / The net energy release would be greater.
____ 22. How does an enzyme influence a biological reaction?
a. / It increases the net energy difference between reactants and products.b. / It decreases the activation energy necessary to initiate the chemical change.
c. / It increases the kinetic energy of reactants, thereby increasing their tendency to collide.
d. / It decreases the kinetic energy of reactants, enabling them to undergo chemical change more easily.
____ 23. Capillary action is the result of adhesion. Which aspect of water is responsible for this?
a. / hydrogen bonds between water and another substanceb. / polar covalent bonds that join molecules of water to other substances
c. / nonpolar covalent bonds that enable water to dissolve other substances
d. / ionic bonds that enable electrons to flow through water and into another substance
____ 25. Which beverage is the best example of a colloid?
a. / black coffee / c. / milkb. / root beer / d. / tea
____ 26. When added to water, how does an acid affect the pH and H+ concentration?
a. / Both pH and H+ decrease.b. / Both pH and H+ increase.
c. / The pH decreases while the H+ increases.
d. / The pH increases while the H+ decreases.
____ 27. Which element is found in proteins but not carbohydrates or lipids?
a. / C / c. / Nb. / H / d. / O
____ 28. In humans and other multicelluar organisms, which substance plays a central role as an energy source?
a. / carbohydrate / c. / proteinb. / fat / d. / water
Figure 7-3
____ 29. What is the approximate size of A in Figure 7-3?
a. / 400 mm / c. / 700 mmb. / 500 mm / d. / 1000 mm
____ 30. Which of the following pictures in Figure 7-5 most likely approximate the motion phospholipids make in a plasma membrane?
Figure 7-5
a. / A / c. / Cb. / B / d. / D
____ 31. Both Schwann and Virchow developed important theories about cells in the mid 1800s. Which best explains the reason these theories were made within a few years of each other?
a. / Hooke’s Micrographia inspired both theories.b. / New microscopes provided better viewing of cells.
c. / Scientists invented the microscope in the mid 1800s.
d. / The electron microscope was used for the first time.
____ 33. Which statement is true about bacterial cells?
a. / The cells are very large. / c. / They are eukaryotes.b. / The cells have no nucleus. / d. / They have organelles.
____ 34. Cholesterol is repelled by water and can be found between the layers of the phospholipids in the plasma membrane. What can be concluded from this information?
a. / A high cholesterol diet should be avoided.b. / Cholesterol is nonpolar.
c. / Cholesterol is polar.
d. / Cholesterol is repelled by the polar tails.
____ 35. At what point in the process of diffusion is dynamic equilibrium reached?
a. / when the movement of the molecules stops being randomb. / when the molecules are mixed and stop moving
c. / when the rate of change in the solution slows by one half
d. / when there is continuous movement but no change
____ 36. What is a major difference between facilitated diffusion and active transport?
a. / Active transport moves substances against the concentration gradient.b. / Active transport uses proteins in the process.
c. / Facilitated diffusion moves molecules through the plasma membrane.
d. / Facilitated diffusion requires large amounts of energy.
____ 37. Algal cells are placed in an isotonic solution. Additional amounts of solutes are slowly added to the solution. What happens to the cells?
a. / They will begin to swell. / c. / They will stay the same.b. / They will burst. / d. / They will shrink.
____ 38. Which of the following is an example of passive transport?
a. / endocytosis / c. / facilitated diffusionb. / exocytosis / d. / Na+/K+ ATPase pump
____ 39. Which of the diagrams in Figure 8-1 show how energy is produced in a cell?
Figure 8-1
a. / A / c. / Cb. / B / d. / D
____ 40. What is the main purpose of the cycle shown in Figure 8-3?
Figure 8-3
a. / sugar production / c. / production of ADPb. / destruction of CO2 / d. / production of NADP-
____ 41. In which types of organisms does the process shown in Figure 8-4 take place?
Figure 8-4
a. / plants only / c. / neither plants nor animalsb. / animals only / d. / both plants and animals
____ 42. During photosynthesis light energy is converted to the energy in chemical bonds. What also happens according to the predictions of the second law of thermodynamics?
a. / chemical energy is converted to light energyb. / matter is lost in the process
c. / heat is released in the process
d. / the light and chemical energy are equal
____ 43. What results from the removal of a phosphate group from ATP?
a. / the production of mechanical energyb. / the release of energy
c. / the creation of energy
d. / the absorption of energy by chlorophyll
____ 44. Infer why chloroplasts are found mostly in the leaves of plants.
a. / The large surface area of leaves allows for maximum light absorption.b. / The waxy coating on the surface of leaves helps prevent evaporation.
c. / Chlorophyll interferes with the xylem and phloem in the stems and trunks of plants.
d. / The large surface area of leaves allows for contact with oxygen.
____ 45. Which of the following is an accurate description of how structure enhances function in the thylakoid?
a. / Thylakoid membranes have a large surface area that provides the space needed to hold large numbers of electron-transporting molecules.b. / Thylakoid membranes serve as an impermeable surface that prevents the flow of electrons into the stroma.
c. / Thylakoid membranes can open and close depending on humidity to prevent evaporation from the cell.
d. / Thylakoid membranes act as an oxygen barrier allowing the aerobic steps of photosynthesis to proceed.
____ 46. Which of the following is an accurate summary of chemiosmosis?
a. / Oxygen atoms diffuse down their concentration gradient out of the stroma into the grana through ion channels in the membrane.b. / Hydrogen atoms diffuse down their concentration gradient out of the chloroplasts into the thylakoid membrane.
c. / Hydrogen atoms move up their concentration gradient through active transport out of the thylakoid into the stroma through ion channels in the membrane.
d. / Hydrogen atoms diffuse down their concentration gradient out of the thylakoid into the stroma through ion channels in the membrane.
____ 47. Which of the following are produced by reactions that take place in the thylakoids and are consumed by reactions in the stroma?
a. / carbon dioxide and water / c. / ATP and NADPHb. / carbon dioxide and ATP / d. / ATP and oxygen
____ 48. The energy acquired in photosynthesis is used to make glucose. Where is the glucose made in plants?
a. / in the thylakoid / c. / in the stromab. / in the thylakoid membrane / d. / outside the chloroplast
____ 49. The reactions of the Calvin cycle are not directly dependent on light, but they usually do not occur at night. Which of the following statements explains why not?
a. / The Calvin cycle depends on products of light reactions.b. / Carbon dioxide is not available at night.
c. / It is too cold at night for reactions to take place.
d. / Most plants do not make the 4-carbon compounds that would be needed for the Calvin cycle to occur at night.
____ 50. Where does the oxygen used in cellular respiration end up?
a. / water / c. / NADHb. / ATP / d. / glucose
Completion
51. When atoms share electrons equally, they form a(n) ______bond.
52. When a mixture or substance changes color or heats up, this provides evidence that a ______has taken place.
53. Molecules that have an unequal distribution of charges are called ______molecules.
54. The electrostatic attraction between adjacent water molecules is called a(n) ______bond.
55. The movement of protons during ATP production is called ______.
56. Hydrogen ion concentration is ______outside the thylakoid membrane than inside.
57. Light-absorbing colored molecules called ______are found in the thylakoid membranes of photosynthetic organisms.
58. The membrane-bound final receptor of electrons from photosystem I is ______.
59. ______is the final stage of aerobic respiration.
60. A group of accessory pigments responsible for the yellow and orange color in carrots and sweet potatoes are ______.
Short Answer
Figure 6-4
61. How many electrons are in the third energy level of a magnesium atom? Refer to Figure 6-4.
62. Which compound shown in Figure 6-4 is formed by covalent bonding? Explain.
63. In plants, cells that transport water against the force of gravity are found to contain many more mitochondria than do some other plant cells. What is the reason for this?
64. Folded membranes have important uses in the cell. Describe at least four of these uses.
65. The cell theory includes three basic principles. Which of these principles was the last to be reported? Explain the reason that this principle was the last to be understood.
66. For what reason do scientists believe that prokaryotic cells are similar to the first organisms on Earth?