UNIT. Review SUGGESTED ANSWERS WHAT DO YOU REMEMBER? 1. (a) 2. (b) 3. (d) 4. (c) 5. (b) 6. (c) 7. (a) 8. (c) 9. (a) 10. (b)11. (d)

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1 UNIT B Review SUGGESTED ANSWERS WHAT DO YOU REMEMBER? 1. (a) 2. (b) 3. (d) 4. (c) 5. (b) 6. (c) 7. (a) 8. (c) 9. (a) 10. (b)11. (d) 12. False. Animals have levels of organization (a hierarchy) for structure and function, including cells, tissues, organs, and organ s. 13. False. The tissue responsible for transporting materials around a plant is called the vascular tissue. 14. False. The phase of the cell cycle during which DNA replicates is called interphase. 15. True 16. False. The part of a plant that contains only the male sex cells is the pollen. 17. False. Cancerous tumours may form when cells do not stop dividing. 18. False. The main function of leaves on a plant is to carry out photosynthesis. 19. False. When there is a good supply of water, the guard cells swell to open the stomata. 20. False. Arteries carry oxygenated blood from the lungs to other parts of the body. 21. bone marrow; umbilical cord blood 22. nerve; muscle 23. urinary; digestive; circulatory; respiratory 24. nervous 25. water 26. pairs; bend; straighten 27. high; low 28. differentiation 29. (a)(iii); (b)(v); (c)(iv); (d)(ii); (e)(i) 30. Cells divide for growth, repair, or reproduction. 31. Interphase is the phase that takes place when a cell is not undergoing mitosis or cytokinesis. During interphase, cells perform their normal function, grow, replicate DNA, and replicate organelles. 32. A cell needs to duplicate the DNA in the nucleus because both daughter cells need a full set of chromosomes. 33. The sample with more rapid cell division is the one with more cells in different stages of mitosis. 222 Unit B: Tissues, Organs, and Systems of Living Things NEL

2 34. A cell will grow and divide if there are enough nutrients available, if its DNA is intact and not damaged, if it can replicate its DNA, and if it receives signals from the body to enter cell division. 35. Some factors that can increase the risk of cancer are genetic predisposition, smoking, excessive UV exposure, type of food eaten, and carcinogens. 36. The digestive and the circulatory work together to provide nutrients to all cells. The digestive breaks food down so it can be absorbed by the circulatory. The circulatory transports the nutrients to all the cells in the body. 37. Plants do not have to move from place to place to survive because they can produce their own food by the process of photosynthesis that uses sunlight, carbon dioxide, and water to produce sugars for the plant. 38. Sample answer: One of the four types of tissues found in animals is epithelial tissue. Its structure thin, smooth sheets of tightly-packed cells supports its function of keeping the animal from dehydrating by creating a water-resistant barrier. Its structure also allows materials to move through the respiratory and digestive s by providing a smooth lining for these s. WHAT DO YOU UNDERSTAND? 39. Roots of carrots are larger than grass roots because they are used to store starch. 40. Regeneration of tissue in the human body can be the mending of a broken bone, the healing of a cut on skin, or the healing of a torn muscle. 41. (a) Sample answer: Photosynthesis and cellular respiration are similar in that both are chemical reactions and both occur within cells. Both reactions involve the same components: carbon dioxide, water, glucose, oxygen, and energy. (b) Photosynthesis and cellular respiration differ because cellular respiration occurs in both plants and animals, whereas photosynthesis occurs only in plants. They also differ because photosynthesis stores energy in chemical bonds, cellular respiration releases energy in chemical bonds. 42. Mitosis in plant and animals cells is the same. During cytokinesis, plants form a cell plate between the two new daughter cells. Animals have no cell plate; the cellular membrane merely pinches off to create two new daughter cells. Animals Plants prophase metaphase anaphase telophase cytokinesis prophase metaphase anaphase telophase cytokinesis 43. Rate of cell division Level of specialization Length of mitosis Appearance of cell Ability to move healthy cells low high long cycle regular do not usually migrate cancer cells high none short cycle irregular, odd shaped able to migrate 44. MRI uses high powered magnets to obtain images inside of the body. It is used to diagnose brain injuries and many kinds of body disorders and injuries. An endoscope can use light to see inside of the body. It can diagnose cancers and look at intestinal disorders. An angiogram uses a special fluorescent dye and X-rays to get a view of the health of coronary arteries. NEL Review 223

3 45. The greater the cell size, the less likely it is that the cell will be able to efficiently diffuse materials in and out. As the cell gets bigger, the volume increases faster than the surface area, meaning the volume to surface area ratio decreases, so diffusion is less efficient. 46. Smooth muscle contracts involuntarily in places like the stomach. Skeletal muscle contracts voluntarily in places like the arm or leg. Cardiac muscle exists only in the heart and is involuntary but is stimulated by nerve impulses. 47. Stem cells can be used to develop a variety of specialized cells. By making specialized cells behave as stem cells, they can be used to repair damage to the original tissue. 48. Xenotransplantation transplants organs or tissues from non-human animals into humans. Regular organ transplants transfer organs and tissues from human to human. 49. Some plants use the wind to carry pollen from one plant to another. In this case, the lighter the pollen, the farther it is likely to travel in the wind and reach another plant of the same species. 50. A plant with a very thick cuticle would be found in a dry environment, such as a desert. 51. A frog using its skin as a respiratory surface is an advantage because the frog does not need to have its head above water to take in oxygen. It is a disadvantage because the frog must keep its skin wet at all times to allow gas exchange. 52. Sample answer: Plants are used in building materials. Plants are also used to make fabric for clothing, paper and books, cosmetics, and dyes. 53. (a) Animal epithelial tissues make up the skin and serve as lining for intestines and other organs. They provide a protective outer surface. (b) Plant dermal tissues protect and cover the outside of plant surfaces. (c) Both are similar because they form a protective outer covering. They are different because epithelial tissue lines organs inside animals, but dermal tissue is strictly an outer covering in plants. 54. In plants, xylem and phloem transport water, minerals, and nutrients passively up and down the plant. There is no active pumping or moving. In animals such as mammals the heart actively pumps blood through a set of tubes (veins and arteries). 55. Animals must eat other things (plants or other animals) to obtain nutrients. Plants make their own nutrients using photosynthesis. The few nutrients that plant cannot make are obtained through roots in the ground. 56. Animal organism organ organ tissue cell example polar bear circulatory heart cardiac muscle cell Plant organism body plant part tissue tissue cell example oak tree shoot leaf dermal epidermal guard cell 57. Natural type Artificial success Plants from buds, cuttings tissue culture propagation very successful Animals asexual reproduction in insects, lizards, some birds frogs, mice, sheep clones are often not healthy 224 Unit B: Tissues, Organs, and Systems of Living Things NEL

4 58. human body respond to changes get rid of wastes grow obtain energy nervous musculoskeletal circulatory respiratory digestive 59. blood red blood cells, which transport oxygen white blood cells, which fight infection platelets, which help blood to clot plasma, which is a fluid that carries blood cells 60. (a) The endoplasmic reticulum is a network that allows materials to move around the cell similar to the way the circulatory allows materials to move through the body. (b) Golgi bodies package up materials that are to be removed from cells. It is similar to the digestive, which digests food and excretes waste from the body. (c) The cytoplasm helps the cell maintain its shape. The skeletal of the body serves a similar function. SOLVE A PROBLEM 61. Sample answer: If plants growing at the surface of the pond covered the entire pond surface, I predict that the plants on the bottom of the pond would die, because they would not receive any sunlight. 62. An advantage of a body with specialized cells is that the body can perform many more functions due to the specialization of the cells. However, specialized cells mean that, if one is harmed by injury or disease, other cells may not be able to take over the function of the damaged cells. 63. A deficiency of hemoglobin would reduce the amount of oxygen that the circulatory could transport. In order to make up for the oxygen deficiency, the circulatory would have to work harder and faster to supply the body with enough oxygen. 64. (a) Percentages are shown in the table below. Cell stage or phase Area 1 Area 2 Percentage in each stage/phase Area 1 Percentage in each stage/phase Area 2 Time for each phase (h) Area 1 interphase prophase Time for each phase (h) Area 2 metaphase anaphase telophase cytokinesis Total cell count NEL Review 225

5 (b) Circle graph should show the percentages given in the table. A sample table for Area 1 is shown below: 8 % cytokinesis 3 % telophase 2 % anaphase 3 % metaphase Percentage in each stage/phase Area 1 12 % prophase 73 % interphase 65. (a) Because skin and blood cells do not have a nucleus, they do not have DNA. Without DNA, they have no instructions (code) for cell division and no chromosomes, so they do not divide. New cells must be produced from specialized cells. (b) Without a nucleus, skin cells could not produce new skin cells. However, the cream might be able to produce new skin cells by stimulating the specialized cells that create skin cells. (c) Sample answer: Tag existing cells with some kind of chemical or fluorescent marker that does not transfer during cell division. Apply the cream. Then reassess the area after the cream has been applied. If cells appear without the marker, they must be new cells. 66. (a) Cells in different parts of the body get worn out at different rates. Also, brain cells, for example, are responsible for memories, so they would need to last for many years if the memory is to last for many years. (b) Injuries to tissues that have long-lived cells, such as brain or bone injuries, would be a lot harder to recover from, because the cells in each place would be likely to regenerate at a much slower pace. 67. (a) The test could expose a person s arms to the Sun, with sunblock applied to only one arm, and measure how fast it takes to get a sunburn. The arm with sunblock should take 60 times longer to show evidence of a burn. The ethics of this test would be questionable, because the subject would be sunburned and be uncomfortable. The subject might also be at a higher risk of developing skin cancer. (b) This product would have no impact on cancer rates, because the sunblock only protects against UVB rays. If the sunblock is to be effective against skin cancer, it will have to protect against UVA rays. 68. (a) Because the people exposed to radiation developed cancers, we know that their rate of cell division was too fast. Radiation damaged the chromosomes, resulting in a high rate of uncontrolled cell division. (b) You would expect to see a higher rate of cells undergoing mitosis in people who lived near the accident and were exposed to radiation. 69. Pesticides could kill the insects that the plants rely on for pollination. Growers might avoid using pesticides if they wanted to produce fruit. 70. (a) To test the effect of ethene, I would have two sealed containers of unripe bananas. I would put a ripe banana into one of the containers and compare the ripening rate of the bananas in two containers. I would expect the ethene-exposed bananas (the one with the ripe banana added) to ripen faster. (b) To make fruit last longer at home by delaying ripening, always keep ripe fruits away from unripe fruits. 71. To demonstrate that vascular tissues connect to all parts of the plant, a dye can be placed in a plant s water source. After 24 hours, cut the plant open and observe to determine whether or not the coloured water was taken up by different parts of the plant. A leaf near the top or stem near the top of the plant can be sliced through to see the coloured dye contained inside the plant parts. 226 Unit B: Tissues, Organs, and Systems of Living Things NEL

6 72. Students answers will vary. To evaluate students responses, check that students have chosen two related organ s and have provided a clear description of how the two organ work together to accomplish specific functions. 73. Sample answer: Gravity can move materials down the plant. Concentration gradients can move materials both up and down plants by the process of diffusion. Also, as water evaporates through the plant s leaves, water in the stem of the plant can be pulled upwards, like water being drawn through a sponge. CREATE AND EVALUATE 74. Dramatizations will vary. Be certain that students have included each phase of the cell cycle in their dramatizations and that each phase and stage is correctly represented. 75. Campaigns will vary. Students campaigns should clearly identify a specific disease, identify a local fundraising activity related to that disease, and effectively promote the selected event. 76. Advantages of growing tall: more sunlight, leaves higher up and out of the reach of ground predators. Disadvantages: more noticeable to predators, more body weight to support, more vulnerable to wind, need longer roots for anchoring the plant, and more nutrients to sustain growth, repair, and reproduction. 77. The friend is not entirely correct. It is true that a plant uses oxygen at night to perform cellular respiration, but not so much that it will use up all the oxygen in a room. 78. Oxygen from the air is taken up through the nose and sucked into the lungs. The lungs are full of little air sacs called alveoli that are coated with moist epithelial tissue. The oxygen gets dissolved in the moist environment and is absorbed into the blood stream. The freshly oxygenated blood gets pumped back into the heart. The heart then pushes the bright red, oxygenated blood through the arteries that will lead to all the parts of the body. As the arteries become progressively smaller, they eventually turn into capillaries, which are only as wide as one red blood cell. Oxygen gets leaves the blood and gets absorbed into the muscle cell, where it is used in the process of cellular respiration to produce energy. 79. Grafting is an example of asexual reproduction because a new, genetically identical apple tree is produced from a single parent. REFLECT ON YOUR LEARNING 80. Sample answer: It was difficult to distinguish cytokinesis from telophase. Sometimes the boundaries of the new cells were not clear. 81. Sample answer: I thought genetic modification was science fiction. Now I understand that it is possible for many organisms, but it does bring technical and ethical problems. 82. Sample answer: I realize that lifestyle choices can affect the likelihood of getting cancer and heart disease. Limiting sunlight exposure, eating a healthy diet, and exercising can help a person avoid cancer and heart disease. 83. (a) The transport and gas exchange s in animals are closely related and function together. The heart pumps blood, which transports oxygen, carbon dioxide, nutrients, and wastes, throughout the animal. In comparison, the transport and gas exchange s in plants do not work together. Xylem and phloem move material through the plant, while guard cells on the surfaces of leaves regulate the flow of gases into and out of the leaves. (b) Sample answer: Yes, it makes sense because animals are more active than plants and therefore need to move materials through the organism at a faster rate. Plants will survive slower rates of material transport. (c) The outer covering of animals and plants could be compared, as well as the way in which the two types of organisms take in their food. NEL Review 227

7 84. Sample answer: Yes, I think a career in imaging technology would allow me to pursue my interest in technology along with my desire to help others. 85. (a) Sample answer: Before studying this unit, I was not sure what was involved in organ donation, but I had a favourable opinion of organ donation. (b) Sample answer: I now better understand the benefits and risks or organ transplantation, and how the process works. My opinion of organ donation is still favourable. WEB CONNECTIONS 86. The ECG shows a spreading electrical wave that starts in the right atrium. The P wave shows this signal spreading through the left and right atria, causing both atria to contract and push blood into the ventricles. The Q-R-S wave begins as the electric signal hits both ventricles (the Q and R part of the wave), spreading all the way to the bottom of the ventricles (corresponding to the S wave). This causes the ventricles to contract, pumping blood to the lungs and to the body. The T wave indicates when both ventricles are relaxed and the heart is reset for another cycle. 87. carnivore small intestine herbivore stomach cecum (appendix) large intestine small intestine 88. (a) Tissue engineering combines tissue culture cells, engineering principles, and materials to repair damaged body tissues. Examples include artificial skin, artificial bone marrow, and artificial liver and pancreas tissue. (b) Sample answer: The heart is an organ that should be considered for future tissue engineering research, because hearts can only come from deceased donors and there is a high demand for hearts for transplant. 89. Sample answer: Skin cancer accounts for about a third of all cancers diagnosed in Ontario. One of the major risk factors for skin cancer is exposure to UV light. So, protect yourself from the Sun by wearing hats and sunscreen. Also, avoid tanning lamps and beds. 90. (a) Colony collapse disorder is a phenomenon in which worker bees in a hive suddenly disappear and the hive does not survive. Colony collapses were reported in North America in 2006 and continued to occur in the years that followed. It has also been observed in Europe. Causes of the collapse are not fully understood. Possible causes include: pesticides, viruses, invasion of mites, climate change, and habitat loss. (b) Student articles will vary. All articles should show student understanding that if too many bee colonies are destroyed by colony collapse disorder, there could be serious consequences to the economy and the food supply. Many key foods such as apples, almonds, cherries, plums, cocoa, watermelon, and cantaloupe all depend greatly on honeybees for pollination. Without bees, these foods and many others may be hard to come by and prices will increase. People that grow these foods, either for their own consumption or for trade, will be negatively affected. 228 Unit B: Tissues, Organs, and Systems of Living Things NEL