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The Cell Teacher’s Guide High/Middle School Editors: Brian A. Jerome, Ph.D. Stephanie Zak Jerome Assistant Editors: Heidi Berry Stephanie Rogers Anneliese Brown Visual Learning Company Brandon, Vermont 1-800-453-8481 www.visuallearningco.com The Cell Reviewers: Mary Cahill Potomac Middle School Mclean, Virginia Wasim Chowdhury, Ph.D. Department of Biological Sciences University of Maryland Baltimore, Maryland Susan Hurstecalderone Holy Cross Chevy Chase, Maryland Use and Copyright: The purchase of this video program entitles the user the right to reproduce or duplicate, in whole or in part, this teacher’s guide and the blackline master handouts for the purpose of teaching in conjunction with this video, The Cell. The right is restricted only for use with this video program. Any reproduction or duplication, in whole or in part, of this guide and the student masters for any purpose other than for use with this video program is prohibited. The video and this teacher’s guide are the exclusive property of the copyright holder. Copying, transmitting or reproducing in any form, or by any means, without prior written permission from the copyright holder is prohibited (Title 17, U.S. Code Sections 501 and 506). 112200 Visual Learning Company 1-800-453-8481 2 The Cell Viewing Clearances The video and accompanying teacher’s guide are for instructional use only. In showing these programs, no admission charges are to be incurred. The programs are to be utilized in face-to-face classroom instructional settings, library settings, or similar instructional settings. Duplication rights are available, but must be negotiated with the Visual Learning Company. Television, cable, or satellite rights are also available, but must be negotiated with the Visual Learning Company. Closed circuit rights are available, and are defined as the use of the program beyond a single classroom but within a single campus. Institutions wishing to utilize the program in multiple campuses must purchase the multiple campus version of the program, available at a slightly higher fee. Discounts may be granted to institutions interested in purchasing programs in large quantities. These discounts may be negotiated with the Visual Learning Company. Visual Learning Company 1-800-453-8481 3 The Cell Table of Contents Page National Standards Correlations 6 Student Learning Objectives 7 Assessment 8 Introducing the Video 9 Video Viewing Suggestions 9 Video Script 11 Answers to Student Assessments 16 Answers to Student Activities 17 Assessment and Student Activities Masters 18 Visual Learning Company 1-800-453-8481 4 The Cell A Message from our Company . . . Dear Educator: Thank you for your interest in the educational videos produced by the Visual Learning Company. We are a Vermont-based, family owned and operated business specializing in the production of quality educational science videos and materials. We have a long family tradition of education. Our grandmothers graduated from normal school in the 1920’s to become teachers. Brian’s mother was an elementary teacher and guidance counselor, and his father was a high school teacher and superintendent. This family tradition inspired Brian to become a science teacher, and to earn a Ph.D. in education, and lead Stephanie to work on science educational programs at NASA. In developing this video, accompanying teacher’s guide, and student activities, our goal is to provide educators with the highest quality materials, thus enabling students to be successful. In this era of more demanding standards and assessment requirements, supplementary materials need to be curricular and standards based - this is what we do! Our videos and accompanying materials focus on the key concepts and vocabulary required by national and state standards and goals. It is our mission to help students meet these goals and standards, while experiencing the joy and thrill of science. Sincerely, Brian and Stephanie Jerome Visual Learning Company 1-800-453-8481 5 The Cell National Standards Correlations National Science Education Standards (Content Standards: 5-8, National Academy of Sciences, c. 1996) Science as Inquiry - Content Standard A: As a result of activities in grades 5-8, all students should develop: • Abilities necessary to do scientific inquiry • Understandings about scientific inquiry Life Science - Content Standard C: As a result of their activities in grades 5-8, all students should develop an understanding of how: • All organisms are composed of cells- the fundamental unit of life. Most organisms are single cells; other organisms, including humans, are multicellular. • Cells carry on the many functions needed to sustain life. They grow and divide, thereby producing more cells. This requires that they take in nutrients, which they use to provide energy for the work that cells do and to make the materials that a cell or an organism needs. Benchmarks for Science Literacy (Project 2061 - AAAS, c. 1993) The Living Environment - Cells (5C) By the end of the 8th grade, students should know that: • All living things are composed of cells, from just one to many millions, whose details usually are visible only through a microscope. Different body tissues and organs are made up of different kinds of cells. The cells in similar tissues and organs in other animals are similar to those in human beings but differ somewhat from cells found in plants. • Cells continually divide to make more cells for growth and repair. Various organs and tissues function to serve the needs of cells for food, air, and waste removal. Visual Learning Company 1-800-453-8481 6 The Cell Student Learning Objectives Upon viewing the video and completing the enclosed student activities, students should be able to do the following: • Understand that all life depends on cells; • Identify the three principles of the cell theory and recognize its importance in studying cells; • Understand that scientists use microscopes to make new discoveries about cells; • Differentiate between a light microscope and an electron microscope; • Differentiate between living cells and non-living cells; • Identify and explain the function of the different structures found in cells, including cell wall, chloroplast, nucleus, nucleolus, cytoplasm, endoplasmic reticulum, ribosome, golgi apparatus, mitochondria, vacuole, and lysosome; • Differentiate between the organization of a plant cell and an animal cell; and • Discuss the specific functions that the different organelles in a cell perform. Visual Learning Company 1-800-453-8481 7 The Cell Assessment Preliminary Test: The Preliminary Test, provided in the Student Masters section, is an assessment tool designed to gain an understanding of student preexisting knowledge. It can also be used as a benchmark upon which to assess student progress based on the objectives stated on the previous pages. Video Review: The Video Review, provided in the Student Masters section, can be used as an assessment tool or as a student activity. There are two main parts. The first part contains questions titled “You Decide” that can be answered during the video. The second series of ten questions consists of a video quiz to be answered at the conclusion of the video. Post-Test: The Post-Test, provided in the Student Masters section, can be utilized as an assessment tool following student completion of the video and student activities. The results of the Post-Test can be compared against the results of the Preliminary Test to assess student progress. Visual Learning Company 1-800-453-8481 8 The Cell Introducing the Video Cells are the building blocks of life. All living organisms contain cells. Explain to the students that although cells are microscopic, each one contains many organelles that allow the cell to function. Before showing the video, ask students to name the parts of a cell that they already know. The most commonly known parts of a cell include the nucleus, cell membrane, and the cell wall. Have one volunteer write the list on the chalkboard. After viewing the video, have students add to the list on the board other organisms not mentioned before the showing. Along with listing the names of the organelles, have the students explain how each organelle enables the cell to function. Video Viewing Suggestions You may want to photocopy and distribute the Student Master, “Video Review.” You may choose to have your students complete this Master while viewing the program or to do so upon its conclusion. The program is approximately 20-minutes in length and includes a tenquestion video quiz. Answers are not provided to the Video Quiz on the video, but are included in this teacher’s guide. You may decide to grade student quizzes as an assessment tool or to review the answers in class. The video is content-rich with numerous vocabulary words. For this reason you may want to periodically stop the video to review and discuss new terminology and concepts. Visual Learning Company 1-800-453-8481 9 The Cell Student Assessments and Activities Assessment Masters: • Preliminary Test • Video Review • Post-Test Student Activity Masters: • The Animal Cell • The Plant Cell • The Cell Theory and Microscopes • Seeing Cells • Vocabulary of The Cell Visual Learning Company 1-800-453-8481 10 The Cell Video ScriptThe Cell 1. All living things have one very important thing in common. They all possess tiny structures that can’t be seen with the naked eye. 2. What are these tiny structures? 3. Flowers possess them. 4. Plants and trees rely on these structures to grow tall and… 5. …to convert radiant energy from the sun to simple sugars that contain chemical energy. 6. Fish use them to carry out their lives in water,… 7. ...and even large animals such as this pelican… 8. …and this sea lion depend on these structures to move, grow, and reproduce. 9. What are the structures on which all life depends? Here is one more clue: they often are called the building blocks of life! 10. These structures are called cells. 11. During the next few minutes we are going to take a look at the general characteristics of cells, their designs,… 12. …and the activities they perform. 13. We are also going to take a look at how cells help human beings carry out their lives. 14. Graphic Transition - Seeing the Invisible 15. Exactly what are cells and how important are they? 16. As we have stated, all life depends on cells. The human body contains not only millions of cells, but hundreds of different kinds of cells as well. 17. Most cells are too small to be seen with the naked eye. 18. For example, this small drop of water contains dozens of single-celled organisms not visible to the naked eye. 19. Using a tool called a microscope, however, these invisible cells become visible. 20. The first microscopes, which contained just a single lens, were similar to a magnifying glass. 21. But in 1590 a man who made reading glasses decided to put two lenses together in a tube and made the first compound microscope. 22. Today, compound light microscopes are widely used. These microscopes let light pass through an object on a glass slide and then through two or more lenses. 23. Convex lenses enlarge the image and bend the light toward the eye. 24. The most common compound light microscopes magnify objects up to 430 or 1000 times their original size, while those with more powerful lenses have even greater magnification power. 25. Objects that are too small to be seen with a compound light microscope can only be viewed with an electron microscope, which has the ability to magnify images up to one million times their original size. Visual Learning Company 1-800-453-8481 11 The Cell Script 26. Rather than using lenses to bend light, electron microscopes use magnetic fields to bend beams of electrons. 27. This electron microscope is called a scanning electron microscope. 28. Scanning electron microscopes are used to study the outside of objects. 29. Graphic Transition- Discovering the Cell 30. Early scientists did not have the high-powered microscopes we use today. 31. Instead, they utilized simple microscopes, such as this one, to explore the microscopic world. 32. One such scientist was the English biologist Robert Hooke 33. You Decide! What’s the object Hooke saw under his microscope? 34. In 1663, Hooke took a piece of cork, cut a very thin slice, and viewed it under the microscope. 35. Looking at the cork he discovered tiny square-shaped forms. He called these structures cells. 36. What Hooke was seeing was not living cells but the remaining cell walls of dead plant cells. 37. Around the same time, a Dutch scientist named Anton van Leeuwenhoek was also… 38. …using a simple microscope to look at living microscopic organisms. 39. He was the first to discover single-celled organisms we know today as bacteria. 40. Graphic Transition- The Cell Theory 41. In 1838 a German botanist, Matthias Schleiden, used the microscope to study… 42. … parts of plants. 43. Schleiden concluded that plants were made of cells. 44. One year later, scientist Theodor Schwann, who had been looking… 45. …at different animal cells, concluded that… 46. …all animals, too, are made of cells. 47. Together, Schleiden and Schwann concluded that all living things are made of cells. 48. In the mid-1850’s, a doctor by the name of Rudolph Virchow stated that new cells do not form on their own. 49. He stated that cells divide to form new cells. 50. In other words, new cells come from previously existing cells. 51. The combined discoveries of Schleiden, Schwann, and Virchow led to what we know today as the cell theory. 52. The cell theory is a fundamental principle of biology and has three major parts. 53. First, it states that all living organisms are made of one or more cells. 54. This ranges from single-celled organisms, such as this bacteria,… 55. …to large organisms such as this horse. 56. Second, the cell theory states that cells are the basic units of structure and function in all organisms. 57. This means that there is no life without cells. 58. Third, the cell theory states that all cells come from previously existing cells. Visual Learning Company 1-800-453-8481 12 The Cell Script 59. As previously stated, new cells do not just magically appear, but come from other cells when they divide. 60. These three main concepts make up the cell theory. 61. Graphic Transition – Organization of the Cell 62. Most cells are smaller than the head of this pin. 63. But, believe it or not, cells are made up of even smaller parts called organelles. 64. Organelles are the structures within cells that break down food, move water, and store nutrients. 65. All parts of a cell are extremely important in carrying out functions in both plants and animals. 66. While both plant and animal cells contain many similar cell structures, there are some distinct differences between plant and animal cells. 67. One difference between plant and animal cells is the structure that surrounds the cell. 68. Plant cells are surrounded by a relatively rigid cell wall. The cell wall is made of cellulose, a strong and tough material. 69. Cell walls enable trees to stand straight and tall. 70. You Decide! Do animals possess a cell wall? 71. Animal cells do not possess a cell wall, possessing only a cell membrane. 72. Plants also possess a cell membrane, but it lies inside the cell wall. 73. In both plants and animals, the cell membrane allows only certain materials to flow into and out of the cell. 74. For example, food and oxygen move through the cell membrane into the animal cell,... 75. …while waste products go through the membrane to exit the cell. 76. Another difference between plant and animal cells is that plants possess structures called chloroplasts. 77. Chloroplasts are organelles that convert light energy into chemical energy that the cell uses to carry out its activities. 78. Chloroplasts enable plants to produce their own food from the energy of the sun 79. Animal cells don’t have chloroplasts. Therefore animals need to obtain their energy by eating food made by other living things, such as fruits, vegetables and meats. 80. Let’s now take a look at some of the other structures found in cells 81. Graphic Transition – The Nucleus 82. Our brains are the control centers of our bodies. 83. The brain guides us through all the activities we take part in during the course of a day. 84. Cells, too, have a control center, called the nucleus. 85. The nucleus acts as the cell’s brain control center, regulating all cellular activities. 86. The nuclear membrane surrounds and protects the nucleus. 87. Like the cell membrane, the nuclear membrane allows only certain materials to pass in and out of the nucleus. Visual Learning Company 1-800-453-8481 13 The Cell Script 88. 89. 90. 91. 92. 93. Also located in the nucleus is a small, dark, round structure called the nucleolus. The nucleolus is where RNA is built and ribosome pieces are created. Graphic Transition- Cytoplasm You Decide! What is the material seen flowing through this cell? If you said water, then you are close. The liquid is called cytoplasm. Cytoplasm contains a large amount of water as well as many chemicals and structures that help carry out the life processes of the cell. 94. Within the cytoplasm are many organelles that we’ll now explore. 95. Graphic Transition- Endoplasmic Reticulum and Ribosomes 96. This network of roads used to transport cars and trucks is like a cell organelle... 97. ...called the endoplasmic reticulum. 98. Its function is to transport materials such as proteins throughout the cell, or in and out of the cell. 99. The endoplasmic reticulum forms a series of tubular passageways, seen here. 100. Attached to the inner surface of the endoplasmic reticulum and scattered in the cytoplasm are small, round structures called ribosomes. 101. Ribosomes play a very important role in the cell because they contain a chemical,called RNA,that directs the production of proteins. 102. Proteins speed up chemical reactions in the cell, as well as control cell growth and repair. 103. Graphic Transition- Golgi Bodies and Mitochondria 104. This loading dock contains material that has been packaged … 105. …and will soon be transported to other locations. 106. Golgi bodies, or the Golgi Apparatus, are stacks of membrane-covered sacs that package and move particles to the outside of the cell. 107. The Golgi Apparatus can be thought of as the cell’s conveyor belt, transporting material. 108 This electrical generating plant provides energy for thousands of people. 1 109. Similarly, structures called mitochondria are the powerhouses of the cell. 110. These rod-shaped structures seen here supply most of the energy for the cell. 111. They break down food to produce large amounts of energy. 112. Muscle cells, which expend large amounts of energy, also contain many mitochondria. 113. Graphic Transition- Vacuoles and Lysosomes 114. This silo, located on this farm, stores food that will… 115. …eventually be fed to cows. 116. Similarly, vacuoles located in the cell store food and other materials for later use by the cell. They can also store waste. 117. In plant cells, vacuoles are the main area where water is stored. 118. The last cell organelles we’ll explore are lysosomes. Visual Learning Company 1-800-453-8481 14 The Cell Script 119. Lysosomes, seen here, contain enzymes. Enzymes break down large food particles into smaller particles, which are then burned in the mitochondria to provide energy for the cell. 120. Lysosomes also digest old parts of the cell when they lose their effectiveness. 121. For example, as this tadpole grows, its tail cells are slowly digested by the lysosomes until the tail disappears. 122. You Decide! What do lysosomes do with the old tail cells? 123. This material is reused to make new body parts to become an adult frog. 124. Graphic Transition- Summing Up 125. During the past few minutes we have explored many different characteristics of cells. 126. We studied how different scientists have made many different discoveries about cells using microscopes... 127. ...and how they developed the cell theory, which states that... 128. ...all living things are made of cells, and . . . 129. ...that cells are the basic unit of structure and function in living things . . . 130. ...and that new cells come from previously existing cells. 131. We also explored some of the important differences between plant and animal cells. 132. Finally, we took a look at some of the important organelles in cells, including the nucleus, . . . 133. ...the endoplasmic reticulum, and ribosomes, . . . 134. ...golgi bodies and mitochondria, . . . 135. ...as well as vacuoles and lysosomes. 136. So the next time you see a plant . . . 137. ...or animal, or see other... 138. ...people, think about how all these living things contain cells. You just might look at your world a little differently. Video Quiz Fill in the correct word when you hear this tone. Good luck and let’s get started. 1. All living things possess _____. 2. Robert Hooke discovered cells while looking at a piece of ____. 3. ________ microscopes use magnetic fields to magnify objects. 4. All cells come from ________ _____. 5. _______ are structures within cells that have specific roles. 6. Animal cells do not have a cell ____. 7. _______ are found in plants, and change light energy into chemical energy. 8. The _______ acts as the cell’s control center. 9. _______ is the fluid that fills the cells. 10. __________ break down food to produce energy in the cell. Visual Learning Company 1-800-453-8481 15 The Cell Answers to Student Assessments Preliminary Test 1. cell theory 2. organelles 3. cellulose 4. nucleus 5. mitochondria 6. vacuoles 7. golgi bodies 8. chloroplast 9. chromosomes 10. endoplasmic reticulum 11. false 12. false 13. true 14. true 15. false 16. true 17. true 18. true 19. false 20. true Video Quiz: 1. cells 2. cork 3. electron 4. other cells 5. organelles 6. wall 7. chloroplasts 8. nucleus 9. cytoplasm 10. mitochondria Post Test 1. true 2. true 3. true 4. true 5. false 6. false 7. false 8. false 9. true 10. true 11. chloroplast 12. vacuoles 13. chromosomes 14. cell theory 15. cellulose 16. endoplasmic reticulum 17. golgi bodies 18. nucleus 19. organelles 20. mitochondria Video Review You Decide: A. Hooke saw a piece of cork under his microscope. B. Animals do not possess a cell wall. C. Cytoplasm is the liquid flowing through the cell. D. Lysosomes reuse the material in the old tail to make new body parts for the adult frog. Visual Learning Company 1-800-453-8481 16 The Cell Answers to Student Activities . The Animal Cell Seeing Cells 1. cell membrane 2. mitochondrion 3. nucleolus 4. lysosome 5. endoplasmic reticulum 6. ribosome 7. cytoplasm 8. nuclear membrane 9. nucleus 10. vacuole 11. golgi bodies Questions: 1. The nucleus controls the activities of the cell. 2. The cell membrane determines which materials enter and exit the cell. Observations: Part I: The cork cells are rectangular in shape. There are no materials within the cell walls. You can tell that the cells are not living because they are empty. Part II: You can see organelles in the elodea leaf cells. Examples include chloroplasts, vacuoles, and cytoplasm. The elodea leaf cells are rectangular in shape and green in color due to the presence of chlorophyll. You can tell that the cells are living because it is possible to identify the organelles, including moving chloroplasts. One difference is that iodine kills the cell, ceasing all movement. A second difference is that by killing the cells, the iodine makes it easier to view the organelles. Chloroplasts are oval. Conclusion: Non-living cells are easier to observe because all of the organelles have died, leaving only the cell walls. In order to see the organelles in a living cell, a powerful microscope is needed. Hooke was using a very simple microscope so it is improbable that he saw the cell as clearly as the students were able to. The Plant Cell 1. mitochondrion 2. vacuole 3. chloroplast 4. cytoplasm 5. endoplasmic reticulum 6. ribosome 7. nucleus 8. nucleolus 9. nuclear membrane 10. cell membrane 11. cell wall 12. golgi bodies Vocabulary 1. cell theory, g 2. cellulose, a 3. golgi bodies, c 4. nucleus, j 5. chromosomes, h 6. cytoplasm, e 7. endoplasmic reticulum, f 8. ribosomes, b 9. mitochondria, d 10. vacuoles, i The Cell Theory and Microscopes Part I: 1. B 3. A 2. B 4. D Part II: 1. F 4. F 2. T 5. T 3. T Part III: Student essays will vary. Visual Learning Company 1-800-453-8481 17 Assessment and Student Activity Masters 18 The Cell Name___________________ Preliminary Test Directions: Fill in the blank with the correct word. A list of possible answers is provided at the bottom of the page. 1. The _____________ states that all cells come from previously existing cells. 2. The smaller structures that make up cells are called _____________. 3. _____________ is the material that makes up the cell wall in plants. 4. The _____________ acts as the brain of the cell. 5. _____________ are the powerhouses of the cell and break down food to produce large amounts of energy. 6. _____________ are the parts of the cell responsible for storage of food, materials, and waste. 7. _____________ are stacks of membrane-covered sacs that package and transport protein to the outside of the cell. 8. An organelle that enables a plant to produce its own food is called a _____________. 9. Rod-like structures inside the nucleus that contain DNA, the chemical that acts as a genetic blueprint, are called _____________. 10. A network of tubular passageways in the cell whose function it is to transport materials is called the _____________. chromosomes cell theory ribosomes mitochondria vacuoles chloroplast organelles endoplasmic reticulum nucleus lysosomes golgi apparatus cellulose 19 ©2001 The Cell Name___________________ Preliminary Test Directions: Decide whether the answer is True (T) or False (F). 11.Robert Hooke first discovered cells by looking at a piece of cork under an electron microscope. T F 12.Both plant and animal cells contain cellulose, a strong and tough material that makes up the cell wall. T F 13.Plant cells contain chloroplasts, while animal cells do not. T F 14.The nuclear membrane protects the nucleus by allowing only certain materials to pass in and out. T F 15.Lysosomes contain RNA and direct the production of proteins in a cell. T F 16.A fluid that flows through the cell and helps to carry out the life processes of the cell is called cytoplasm. T F 17.Chromosomes contain DNA. T F 18.Electron microscopes are able to magnify objects too small to be seen with a compound microscope. T F 19.Mitochondria are responsible for packaging and transporting protein to the outside of the cell. T F 20. The nucleolus is located inside the nucleus of a cell. T F 20 ©2001 The Cell Name___________________ Video Review Directions: During the course of the program answer the “You Decide” questions as they are presented in the video. Answer the Video Quiz questions at the end of the video. You Decide: A. What is the object Hooke saw under his microscope? Answer: _______________ B. Do animals possess a cell wall? Answer: _______________ C. What is the material seen flowing through this cell? Answer: _______________ D. What do lysosomes do with the old tail cells? Answer: _______________ Video Quiz: 1. All living things possess ______________? 2. Robert Hooke discovered cells while looking at a piece of ____________. 3. _______________ microscopes use magnetic fields to magnify objects. 4. All cells come from ____________ ___________. 5. ______________ are structures within cells that have specific roles. 6. Animal cells do not have a cell __________. 7. __________ are found in plants, and change light energy into chemical energy. 8. The _________________ acts as the cell’s control center. 9. ___________ is the fluid that fills the cells. 10. ______________ break down food to produce energy in the cell. 21 ©2001 The Cell Name___________________ Post Test Directions: Decide whether the answer is True (T) or False (F). 1. Plant cells contain chloroplasts, while animal cells do not. T F 2. Electron microscopes are able to magnify objects too small to be seen with a compound microscope. T F 3. The nucleolus is located inside the nucleus of a cell. T F 4. The nuclear membrane protects the nucleus by allowing only certain materials to pass in and out. T F 5. Both plant and animal cells contain cellulose, a strong and tough material that makes up the cell wall. T F 6. Mitochondria are responsible for packaging and transporting protein to the outside of the cell. T F 7. Robert Hooke first discovered cells by looking at a piece of cork under an electron microscope. T F 8. Lysosomes contain RNA and direct the production of proteins in a cell. T F 9. Chromosomes contain DNA. T F 10. A fluid that flows through the cell and helps to carry T F 22 ©2001 The Cell Name___________________ Post Test Directions: Fill in the blank with the correct word. A list of possible answers is provided at the bottom of the page. 11. An organelle that enables a plant to produce its own food is called a _____________. 12. _____________are the parts of the cell responsible for storage of food, materials, and waste. 13. Rod-like structures inside the nucleus that contain DNA, the chemical that acts as a genetic blueprint, are called _____________. 14. The _____________ states that all cells come from previously existing cells. 15. _____________ is the material that makes up the cell wall in plants. 16. A network of tubular passageways in the cell whose function it is to transport materials is called the _____________. 17. _____________ are stacks of membrane-covered sacs that package and transport protein to the outside of the cell. 18. The _____________ acts as the brain of the cell. 19. The smaller structures that make up cells are called _____________. 20. _____________ are the powerhouses of the cell and break down food to produce large amounts of energy. lysosomes golgi apparatus cell theory chloroplast organelles vacuoles cellulose chromosomes nucleus endoplasmic reticulum mitochondria ribosomes 23 ©2001 The Cell Name___________________ The Animal Cell Background: Recall from the video that the internal structures of a cell are called organelles. In this activity you will identify the different organelles of an animal cell. Directions: Use the vocabulary words listed below to label the parts of the animal cell. It may help to refer to a textbook with a diagram of an animal cell to complete this activity. Answer the questions beneath the diagram. 1. 11. 10. 9. 2. 3. 8. 7. 4. 6. 5. vacuole endoplasmic reticulum cell membrane nuclear membrane golgi bodies ribosome cytoplasm lysosome mitochondrion nucleus nucleolus Questions: 1. What is the function of the nucleus? 2. What is the role of the cell membrane? 24 ©2001 The Cell Name___________________ The Plant Cell Directions: Choose from the vocabulary words listed below to label the parts of the plant cell. It may help to refer to a textbook with a diagram of a plant cell to complete this activity. 12. 11. 10. 1. 2. 9. 8. 7. 3. 4. 6. 5. vacuole endoplasmic reticulum cell membrane nuclear membrane golgi bodies ribosome cytoplasm mitochondrion 25 nucleolus chloroplast nucleus cell wall ©2001 The Cell Name___________________ The Cell Theory and Microscopes Directions: Read the passage below about how new discoveries and improvements in technology led to the development of the cell theory. Use this information to answer the questions on the following page. Cells and Microscopes In today’s world, a great deal is known about microscopic life. We can picture microorganisms as if they are tangible objects we can pick up and hold. Imagine if you were living in the 1600’s and all that you know of can be seen with the unaided eye. During this time, people believed in spontaneous generation, which means that living things originate spontaneously out of material such as dust or mud. When a few Dutch eyeglass makers invented a microscope in the late 1500’s, it was one of the biggest breakthroughs in biology. It magnified objects up to 9 times their size. In 1674, a Dutch scientist named Anton van Leeuwenhoek invented a simple, hand held microscope. He examined living cells in substances like pond water and blood. He observed things that no one had ever seen before. His microscope magnified objects up to 270 times their size! As new microscopes were invented, new hypotheses about cells were developed. A hypothesis is a scientific prediction that can be tested. In 1665, the English scientist Robert Hooke used a microscope to observe thin slices of cork. He noticed spaces separated by walls and referred to these spaces as cells, meaning “little rooms.” A German botanist named Matthias Schleiden made the next discovery concerning cells. In 1838, he reported that all plants are made of cells. The following year, German zoologist, Theodor Schwann, concluded that animals are also made of cells. Two decades later, Rudolf Virchow, a pathologist, inferred that all cells come from preexisting cells. These new pieces of evidence developed into a more accepted observation in science called the cell theory. The cell theory consists of the following three principles: 1) cells are the basic units of life; 2) all organisms are made of one or more cells; and 3) all cells arise from existing cells. A new principle has been added to the cell theory in its modern form. Part four of the cell theory states that cells contain the hereditary information of the organisms of which they are a part, and this information is passed from parent cell to daughter cell. This addition to the cell theory was due, in part, to the development of more powerful microscopes Today we commonly use compound light microscopes. Compound light microscopes use lenses to bend beams of light and can magnify objects up to 2000 times their size. In 1931, a man named Ernest Rusk built the first electron microscope. The electron microscope uses a magnetic field to bend beams of electrons and can magnify objects up to 1,000,000 times their size. The latest technology available in microscopy is called a scanning interferometric apertureless microscope. This microscope uses the principles of a light microscope, but has the potential to allow imaging of single atoms! Science and technology have come a long way since the 1600’s. 26 ©2001 The Cell Name___________________ The Cell Theory and Microscopes (cont.) Directions: Part I: Circle the correct multiple choice answer. Part II: Decide whether the statement is True (T) or False (F). Part I 1. Which microscope represents the most recent development? A. simple microscope B. scanning interferometric apertureless microscope C. compound light microscope D. electron microscope 2. The first microscope was invented in the: A. late 1600’s C. early 1600’s B. late 1500’s D. early 1500’s 3. Rudolph Virchow was a: A. pathologist B. German zoologist C. German botanist D. English scientist 4. Spontaneous generation means: A. hereditary information is passed from a parent cell to a daughter cell B. all cells arise from existing cells C. life comes only from other life D. living things can originate from anything Part II 1. Electron microscopes can only magnify objects up to 1000 times their size. 2. The modern cell theory has four principles. 3. Robert Hooke was the first person to use the term “cell.” 4. A theory is a scientific fact. 5. The latest technology in microscopy allows imaging of particles as small as atoms. T T T T T F F F F F Part III – Think about how far science has come since the 1600’s. Write a short essay about what you think new developments in technology could mean for the cell theory. Presently, a microscope is available that enables us to view the smallest unit of matter known to humans, the atom. Do you think there are organisms smaller than the atom that we still do not have the technology to see? What would be possible implications of such a discovery? 27 ©2001 The Cell Name___________________ Seeing Cells Background: The English scientist Robert Hooke discovered the cell by examining a piece of cork under a microscope. In this lab, you will observe what Robert Hooke discovered and compare it to the cell of a living organism. Objective: In this activity you will use a microscope to locate structures in a cell, compare living and non-living cells, and describe the shapes of cells. Materials: microscope slides cover slip razor blade medicine dropper forceps water large cork stopper elodea leaf iodine staining solution Procedure: Part I:Cork 1. Your teacher will prepare a slice of cork thin enough for microscopic examination. 2. Place the cork slice in a small drop of water on a slide. Using your medicine dropper, add a drop of water to the top of the cork slice and cover it with a cover slip. 3. Observe the cork under low power and draw what you see below: 4. Observe the cork under high power. Draw what you see below, paying attention to the shapes of the cells. Label the cell wall. Observations: 1. What is the general shape of the cork cells? 2. Does there appear to be any materials within the cell walls? 3. How can you tell that the cells in cork are non-living cells? 28 ©2001 The Cell Name___________________ Seeing Cells (cont.) Part II: Elodea Leaf 1. Using your forceps, place your leaf in a drop of water on a slide and add a cover slip. 2. Examine the leaf under low power and note the shape of the cells. Find a section of the leaf where the cells appear most clearly. 3. Center the clearest part of the leaf. While under high power, use the fine adjustment to focus the microscope. 4. Look for small moving bodies. Note the direction in which they are moving. 5. Make a new wet mount by placing a different elodea leaf in a drop of the iodine staining solution and covering it with a cover slip. 6. Observe the leaf under high power. Draw what you observe in the space provided: Observations: What structures do you see in the elodea leaf cells that you did not see in the cork cells? What is the general shape and color of the elodea leaf cells? In the slide prepared with water, how can you tell that the elodea leaf cells are living? What are two main differences between the slide of the elodea leaf that was prepared using water and the slide of the elodea leaf that was prepared using the iodine staining solution? 1) 2) What is the general shape of the chloroplasts? Conclusion: Was it easier to observe living cells or non-living cells? Think about the type of microscope you used. Do you think Robert Hooke saw the very same thing you saw in this lab? Explain the reasons for your answers. 29 ©2001 The Cell Name___________________ Vocabulary of The Cell Directions: Unscramble the following vocabulary words and match each word with its correct definition. ___ 1. lcel rhotye ___ 2. slceuleol a. a strong and tough material that makes up a cell wall b. round structures that contain a chemical called RNA, sometimes attached to the endoplasmic reticulum ___ 3. ioglg edbiso ___ 4. lsunceu ___ 5. seomcmshroo c. membrane-covered sacs that package and transport protein to the outside of the cell d. rod-shaped structures that supply most of the energy for the cell, sometimes referred to as the powerhouse of the cell ___ 6. tmsaoyclp ___ 7. sadocielnmp urtmlueci ___ 8. oseriboms e. fluid that flows through the cell, containing a large amount of water, as well as many chemicals and structures f. network of tubular passageways that transports materials throughout the cell ___ 9. ratmohnidoci ___ 10. sovaluce g. all living things are made of cells; cells are the basic units of structure and function in an organism; and all cells come from previously existing cells h. found inside the nucleus, these dark, rod-like structures contain proteins and DNA i. parts of the cell where materials are stored j. sometimes referred to as the cell’s brain, it regulates all cellular activities 30 ©2001