Cells Unit GOALS AND OBJECTIVES. The student will become familiar with the use of the compound microscope.

Transcription

1 Cells Unit GOALS AND OBJECTIVES GOALS The student will become familiar with the use of the compound microscope. The student will become familiar with the basic parts and functions of the cell. OBJECTIVES At the end of this unit the students should be able to: 1. Accurately identify the parts of the compound microscope. 2. Exhibit proper use of a compound microscope. 3. Demonstrate how to make a wet mount slide. 4. Make a drawing of objects viewed through the eyepiece of the microscope. 5. Place a slide on the microscope and use correct procedures to focus at low, medium and high magnification. 6. Calculate the power of magnification given the powers of the eyepiece and the objective lens. 7. Identify the parts of a typical pant and animal cell. 8. Explain the functions of the typical cell parts. 9. Explain the purpose of mitosis. 10. Explain the value of diffusion and osmosis to living cells. 1

2 Parts of the Microscope Name the parts of the microscope. Write the name of the part on the corresponding line at the bottom of the page

3 Microscope Parts Lab Introduction In this lab you will be practicing your skills in the identification of microscope parts. You will identify microscope parts by how they feel. The idea is that if you can identify the parts without seeing them then it will be much easier to identify them later by sight. Materials 1. Work with one partner. 2. Obtain the following: 1 blindfold, 1 compound microscope. Methods 1. Student A will blindfold student B. 2. Mr. Stout will point to various parts of the microscope. 3. Student A will place student B s hand on that part of the microscope. 4. Student B will whisper the name of the part to student A. 5. Student A will write that answer on student B s paper. 6. Students A and B will exchange roles. Round 1 Answers Round 2 Answers Question Number Part Name Question Number Part Name

4 Introduction to the Microscope Parts of the Compound Light Microscope o The ocular lens magnifies the image 10x. o The low-power objective magnifies the image 10x. o The high-power objective magnifies the image 40x or 43x. o The revolving nosepiece holds the objectives and can be turned to change from one magnification to the other. o The body tube maintains the correct distance between the ocular lens and objectives. o The coarse-adjustment knob moves the body tube up and down to allow focusing of the image. o The fine-adjustment knob moves the body tube slightly to bring the image into sharper focus. o The stage supports a slide. o Stage clips hold the slide in place for viewing. o The diaphragm controls the amount of light coming through the stage. o The light source provides light for viewing the slide. o The arm supports the body tube. o The base supports the microscope. 4

5 Care of the Microscope 1. Always pick up and carry the microscope with one hand on the neck, and place the other hand under the base. 2. When placing the instrument on the table, do it gently and keep it away from the edge. The top of the table should be clear of all other objects. 3. Use only lens paper supplied by Mr. Stout to clean your microscope. Never use a handkerchief, clothing, or any other material. Keep your fingers off the lenses: fingertips and eyelashes have an oily film which should be removed with lens paper. 4. Before putting the microscope away, turn the low power objective lens into place over the center of the stage. Then lower the body tube with the coarse adjustment knob so that the microscope can fit into the shelf. Wrap the cord around the base, and place the cover over the microscope. Making a Wet Mount Slide 1. Draw the smallest smiley face that you can on the corner of a sheet of paper. Cut it out with a pair of scissors. 2. Place the face in the center of a depression slide. 3. Using a pipette add two drops of water. 4. Gently place a cover slip on top of the slide. If an air bubble forms remove the slide, and repeat steps 2, 3, and 4. 5

6 Using the Microscope 1. Place the slide on the stage so that the object to be viewed is over the opening in the stage. 2. Put the low power objective lens in place. 3. Use the coarse adjustment knob to lower the body tube and low power objective as close to the slide as possible. 4. Look through the ocular lens (try to keep both eyes open) and turn the coarse adjustment knob slowly so that the body tube moves upwards. 5. After about 1/4 turn of the coarse adjustment knob the object on the slide comes into focus. Adjust the slide so that the object will be in the center of your field of view. 6. Use the fine adjustment knob to zero in on your slide. 7. When the object to be viewed is in the center of the slide and in focus, you may turn the nose piece so that the medium power objective lens is in place. Carefully center the slide. 8 You may now turn the high power objective in place. Follow the same procedure used with the medium power. DO NOT USE THE COARSE ADJUSTMENT KNOB WHEN THE OBJECTIVE LENS IN ANY POSITION EXCEPT LOW POWER!! 9 Adjust the iris diaphragm so that the optimum amount of light is obtained. More is not always better. 6

7 Summary Questions What happens to the image in the field of view when you move the object to the right? What happens to the image in the field of view when the slide is moved toward you? When you switch from low to medium or high power are you seeing more or less of the specimen? Explain. What happens to the brightness of the object as you change to higher powers? What is the function of the iris diaphragm? What is the total magnification if the eyepiece is 10 and the objective is 40x? 7

8 Drawing What You See Background Information There are two major objectives for this lab. The first is to provide practice in using the compound microscope. The second is to provide instruction in making lab drawings. Materials Obtain the following: Your microscope sample(s) 1 compound microscope 1 cover slip 1 slide. Method 1. Focus on your specimen. Try all three powers until you find the one that provides the most interesting view. 2. Prepare a lab drawing of your specimen: A. Draw your specimen. B. Label your specimen. C. Write the power of the microscope. D. Write the date. 3. Follow steps one and two for the 4 samples. You will need to use other students samples for your last three drawings. 8

9 Life in a Drop of Water Just as good building tools can help a carpenter produce a fine home, so can good scientific tools aid a scientist in a variety of endeavors. In this activity you will use one of the basic tools of life science: a microscope, a tool that lets scientists study worlds too small to be seen with the unaided eye. Materials: q Microscope q Coverslip q Medicine dropper q Glass slide q Pond Water Procedure: 1. Make sure that your microscope is in the correct position before you use it. 2. There are several lenses on a microscope. The lens nearest the eye is called the ocular. The lenses closest to the slide are called the objectives. Note that each lens has a number etched on it. The number tells you how many times a particular lens magnifies the image that is viewed through it. Note the number on the ocular and the number on the smallest objective lens. Multiply one number by the other. This will tell the total magnification when these two lenses are used together. Enter the magnification near any drawing you make of what you observe. 3. Retrieve a glass slide. You will make a slide of a drop of pond water. Place one drop of aquarium water in the center of your slide. 4. Pick up one of the coverslips and carefully lower the coverslip onto the drop of water with proper technique. 5. Place the slide on the microscope. Make sure the smallest, or low-power, lens is in position. Look through the ocular. Carefully turn the coarse adjustment knob until the image is in focus. Use the fine adjustment knob to get a clear image. Move the slide slowly back and forth. Draw what you observe. 6. Repeat the procedure with a drop of tap water. 9

10 Observations: Draw what you observe in the space provided. q Pond Water q Tap Water 10

11 1. What kinds of things did you observe in the drop of water from the aquarium? 2. Did these organisms move around or remain in one place? 3. What did you observe in the drop of tap water? 4. How can you explain the differences you observed in the aquarium water and the tap water? 11

12 Plant and Animal Cells At the end of this lab: You will be able to compare and contrast plant cells and animal cells using a microscope,you will be able to identify the various parts of plant and animal cells You will be able to adjust the microscope so that they can distinguish the features of cells Materials: Forceps Eye dropper Onion leaf Microscope Microscope slide Coverslip Toothpicks Methylene blue stain Paper Towels As we have talked about thus far, all living things are made up of cells. Cells are the basic units of structure and function of living things. There are many different types of cells. Whether they are plant or animal cells, most cells share certain characteristics. Animal and plant cells do have some differences, however. It is your job to determine what these differences and similarities are. CAUTION: You will be using microscopes today. Please handle them in the proper way. Procedure: Part A: Examining Plant Cells 1. Put some water from the tap into a beaker. Using an eye dropper, put a drop of the water onto the center of a clean slide. Please be careful; the slide is made of glass! 2. With the forceps, remove a leaf from the Onion plant and place it on the slide. Make sure that the leaf is flat. If it is folded, straighten it with the forceps. 3. Carefully place a coverslip over the drop of water and Elodea leaf. 4. Place the slide on the stage of the microscope with the leaf directly over the opening in the stage. Attached to this lab is a diagram of a microscope similar to the one that you are using. Refer 12

13 to this if you forget where a certain part is. 5. Using the low-power objective lens, locate the leaf under the microscope. Turn the coarse adjustment knob until the leaf comes into focus. When you have focused the leaf, have Mr. Stout check to see if it is focused correctly. 6. Switch to the high-power objective lens. Focus ONLY using the fine adjustment knob. Using the coarse adjustment knob will cause the slide to break. CAUTION: When turning to the high-power objective lens, you should always look at the objective from the side of your microscope so that the objective lens does not hit or damage the slide! 7. Observe the cells of the Onion leaf. Draw and label what you see. High-Power Objective Magnification: Onion Cells (plant cells) 8. Carefully clean and dry your slide and coverslip. 13

14 Part B: Examining Animal Cells 1. Put another drop of tap water in the center of a clean slide. 2. Using the flat end of a toothpick, gently scrape the inside of your cheek. CAUTION: Be extremely careful when scraping the inside of your cheek!! 3. Stir the water on the slide with the end of the toothpick to mix the cheek cells with the water. Throw the toothpick away in the trashcan when you are done. 4. Put one drop of methylene blue stain directly on top of the drop of water containing cheek cells. CAUTION: Methylene blue is a STAIN-THIS MEANS IT WILL STAIN YOUR HANDS AND CLOTHES IF YOU COME INTO CONTACT WITH IT!!! 5. Wait about one minute, then carefully place a coverslip over the stained cheek cells. 6. To remove the stain from under the coverslip and replace it with clear water, place a piece of paper towel at the edge of one side of the coverslip. 7. Then place a drop of water at the edge of the coverslip on the other side. The stained water under the coverslip will be absorbed by the paper towel. As the stain is removed, the clear water next to the coverslip on the opposite side will be drawn under the coverslip. 8. Place the slide on the stage of the microscope with the center of the coverslip directly over the opening in the stage. 9. Using the low-power objective lens, locate a few cheek cells under the microscope. 10. Switch to the high-power objective lens. Use only the fine adjustment knob to focus. CAUTION: When turning to the highpower objective lens, you should always look at the objective from the side of your microscope so that the objective lens does not hit or damage the slide. 11. Observe some cheek cells. Draw and label what you see. Be sure to record the magnification. 14

15 High-Power Objective Magnification: Cheek Cell (animal cell) 12. Carefully clean and dry your slide and coverslip. 15

16 Analysis and Conclusions: 1. Describe the shape of the Elodea cells and the cheek cells. 2. a. How are plant and animal cells similar in structure? b. How are plant and animal cells different? 3. Why are stains such as methylene blue used when observing cells under a microscope? 4. How is the cell wall different from the cell membrane? 5. Explain why you could not use an oak leaf in place of an Elodea leaf in this investigation? 6. If you were given a slide containing living cells, how would you identify the cells as either plant or animal? 16

17 CELL POSTER REQUIREMENTS 1. You will have three options for the construction of your poster. You may choose from the following: A. An animal cell B. A plant cell C. A comparison of plant and animal cells 2. You may work by yourself, or you may work with one other partner from your class period. 3. Make the cell and its organelles large and easy to see. 4. Your poster should be bright and colorful. You do not have to color organelles so they match their true colors in nature. 5. The organelles must be identified and their functions given. Use lettering that is large, so that it can be read easily. 6. Your name(s), science period, and the date of completion must be displayed on the front of your poster. Name Period 17

18 CELL POSTER GRADE All organelles labeled with functions: (2pts each) Student Teacher cell wall chloroplasts lysosome vacuole cell membrane mitochondrion ribosomes e.r. golgi body nucleus nucleolus cytoplasm Organelles are depicted accurately (5pts) Poster is neat and easy to understand (5pts) Total /34 18

19 Words to Know Active Transport Biology Cell Compound Microscope Cytokinesis Cytologist Cytoplasm DNA Growth 19

20 Homeostasis Living Magnify Nonliving Nucleus Organ Passive Transport RNA Spontaneous Generation Tissue 20

21 THE ULTRA STRUCTURE OF ANIMAL CELLS Introduction: 1. Microscopes were invented in the.(date) 2. The light microscope can magnify up to times. 3. The microscope invented in the 1930 s can magnify up to a million times. SLIDE 1 - GLAND CELLS - HUMAN OIL GLAND (400 X) 4. Draw one of the cells and label the nucleus,cytoplasm, and cell membrane. SLIDE 2 - PLASMA CELL (37,000 X) 5. Draw the cell showing the endoplasmic reticulum, ribosomes, mitochondrion and nucleus. SLIDE 3 - CELL MEMBRANE (400,000 X) 6.The cell membrane consists of two layers of with a layer sandwiched in between. SLIDE 4 - GOLGI BODY AND VACUOLE (26,000 X) 7. The job of the golgi body is to manufacture which are then stored in a. 21

22 SLIDE 5 - MITOCHONDRION (124,000 X) 8. The main purpose of the mitochondrion is to release from nutrients gradually. SLIDE 6 - CENTRIOLE (175,000 X) 9. The job of the centriole is somehow related to the separation of during mitosis. SLIDE 7 - LAMPBRUSH CHROMOSOMES (700 X) 10. The DNA molecule transmits and controls cell activities. SLIDE 8 - STRIATED MUSCLE CELL (45,000 X) 11. A muscle cell or fiber is a long cylinder made of many smaller all running the long way. How do you think advances in the technology of the microscope have helped scientists in the study of cells? 22

23 How do YOU like your potatoes? Objectives: Students will be able to explain the process of diffusion. Students will be able to describe how osmosis occurs. Students will be able to predict what will happen to potatoes immersed in salt and sugar water. Materials: 3 slices of potato 3 petri dishes Salt water Sugar water Tap water Masking tape Marker The cells of living organisms are separated from each other by membranes. These cell membranes are semipermeable. This means that they allow certain substances, water for example, to pass through while keeping others out. Water enters and leaves the cell through osmosis. In this process, water molecules pass through the semipermeable membrane. In this lab, you will be observing the effects of osmosis on a potato using solutions of sugar and salt. Procedure: 1. Gather 3 petri dishes. Using masking tape, label one plain, one salt water, and one sugar water. 2. Place a slice of potato into each of the three dishes. Before moving on, record some observations about EACH potato slice. Be sure to include a description of texture, color, temperature, thickness, hardness, the amount of skin and any other criteria that seems noticeable. 23

24 BEFORE OBSERVATIONS: PLAIN WATER- SALT WATER- SUGAR WATER- 3. There are three large containers in the front of the room labeled as plain water, salt water, or sugar water. Pour enough of each type of water into its appropriate dish until the potato slice is covered. 4. Now you must wait twenty minutes. While you are waiting write down what you THINK the potato slices will look like/feel like at the end of this experiment. Record your predictions on the next page. 24

25 PREDICTIONS: PLAIN WATER- SALT WATER- SUGAR WATER- Twenty Minutes Later 5. Now make observations of each potato slice. How are these slices similar to the ones prior to soakage? How are they different? AFTER OBSERVATIONS: PLAIN WATER- SALT WATER- SUGAR WATER- 25

26 Conclusions: 1. Were your predictions similar to what happened or not? How? 2. What do you think caused the changes in the potato? 3. How is what happened to the potato similar to what happens in a crowded room?_ 4. Explain, in two or three sentences, how osmosis affected the potato slices? 26

27 MITOSIS (MICROSET # 53) INTRODUCTION: 1. All life begins as a. 2. In this set of slides we will be observing the cells of a parasitic, called Ascaris. 3. One reason we use the Ascaris for observation is that its are large and number only. 4. In this set of slides the equatorial plate runs from the of the slide to the and the are on the left and right sides of the plate. SLIDE 1 - THE ZYGOTE (750X) 5. A zygote is the of an animal. 6. There are two masses of chromatin in this cell. One mass was the of the egg and the other mass was from the that fertilized the egg. 7. The are not seen clearly because they are very thin and the cell is thick and round. SLIDE 2 - PRO-METAPHASE (750 X) 8. In this slide the chromosomes are easier to see because they are and. 9. The chromosomes begin to pair up. The horseshoe shaped one is called and the curved one is called. 10. One U - shaped chromosome came from the egg and the other came from the. 27

28 SLIDE 3 - METAPHASE (750 X) 11. In this slide the chromosomes have moved to the. 12. At each pole is found a centriole and a star- like which radiates out to each of the chromosomes. SLIDE 4 - METAPHASE -POLAR VIEW (750 X) 13. This is the same slide as # 3 but viewed from the view. SLIDE 5 - EARLY ANAPHASE (750X) 14. Each of the chromosomes have completed duplication. Now there are U- shaped and bents. 15. The chromosome groups are beginning to move toward the. SLIDE 6 - ANAPHASE (750X) 16. What force do scientists think draws the chromosomes to the poles? 17. Scientists think that the chromosomes become short by twisting into a shape. SLIDE 7 - TELOPHASE (750) 18. The chromosomes have drawn completely apart and the is pinching in. SLIDE 8 - LATE TELOPHASE (750X) 19. The zygote has now formed two. 20. In humans the process is basically the same except that instead of four chromosomes there are. 28

29 CELL ANALOGY REQUIREMENTS 1. The cell and each of its organelles should be compared to another object. 2. You will need to create a presentation to illustrate the comparison. 3. The presentation should start with a slide that contains a TITLE, NAME, and PERIOD. 4. There should be an introduction slide that gives an overview of the cell and the object used in the comparison. 4. You should compare a minimum of 8 organelles and each slide should contain an image of the organelle, an image of the object being compared, and a brief reason that they are similar. 5. The presentation should end with a brief conclusion highlighting the overall similarities that the cell and object to which you compare it. 6. Save your presentation using the following format Tommy Student is a student in my 3 rd period class TommyStudent3CA 29

30 Name: Period Student Teacher Introduction- 5 points Comparisons- 3pts-1 pt. for cell organelle 1 pt. for factory part 1 pt. connection Organelle Conclusion- 5 points Total 30

31 Mitosis Flipbook Rubric Student Teacher Title Page (Name & Period) Introduction- What is Mitosis? Interphase* Prophase* Metaphase* Anaphase* Telophase* Cytokinesis* Overall Appearance Saved in correct format (FirstLastPeriodMitosis) /1 /5 /4 /4 /4 /4 /4 /4 /5 /5 Total /40 *To receive all four points you must include a phase informational slide and three additional slides that show what happens during the phase. 31