NAME: PERIOD: DATE: Unit 2 The Basic Unit of Life Lab (Adapted from lab of same name) State Standard

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1 NAME: PERIOD: DATE: Unit 2 The Basic Unit of Life Lab (Adapted from lab of same name) State Standard In this investigation, you will practice the techniques for making a slide, look at various specimens under the microscope, and compare the parts of a cell found in plants and animals. Materials Microscope, compound Anacharis Leaf Slides (2) Cover slips (2) Medicine dropper Iodine Water Toothpick Onion Lens Paper Procedure: You should always be careful when using the microscope. Put one hand on the arm and the other under the base. Before you use the microscope, make sure that the lenses are clean. Use lens paper ONLY! Using any other kind of paper can scratch the lens. Part A The Letter E 1. Look through the eyepiece. Move the diaphragm around until you see the brightest light you can. This light that you are seeing is called the field of view. 2. Turn the nosepiece until the low power objective snaps into place. The low power is the smaller one. 3. Now you must make a wet mount slide. To do this follow these directions: A. Cut the letter e out of a magazine or newspaper. B. Put the e on a slide and add one drop of water to it. C. Carefully put the cover slip on top of the water and letter e. (See Figure 1) Put your finger here and push. Cover Slip Figure 1 Slide D. Put the cover slip on at angle so that the air gets pushed out the other end. 1

2 4. Put your slide with the letter e on the stage of the microscope. Put the stage clips on top of the slide. 5. Find the letter e under low power first. Move the slide around until it is over the hole in the stage. Use the coarse adjustment knob to get the letter in focus (see it clearly). Make sure that the objective does not hit the slide. If you cannot get it into focus, also use the fine adjustment knob. 6. Look through the microscope and move the slide to the left. Which way does the picture you are seeing go? 7. Look through the microscope and move the slide away from you. Which way does the picture you are seeing go? 8. Draw what you see. After you draw it under low power, turn the nosepiece carefully until the high power objective snaps into place. Only use the fine adjustment knob to focus this. Do not use the coarse adjustment knob! Now draw it under high power. Call the teacher over when you have it on high power. 9. Clean the slide. Throw all solid material in the garbage can and rinse the slide with water. Use Kim wipes to dry the slide and cover slip. Do NOT use paper towels; this will scratch the slide. Low Power High Power Part B Cell Nucleus, Wall, and Cytoplasm Onions can show a cell s nucleus. These can be found in most living cells. The nucleus looks like a round shape inside of each cell. 1. Take a small piece of an onion and peel off the thin layer on the inside. 2. Put the thin layer on a microscope slide. 3. Add one drop of iodine to the slide. If you spill the iodine, wash with water immediately and tell the teacher. Cover the slide with a cover slip. 2

3 4. Look at the cells under both low and high power. Find, draw, and label the cell wall, nucleus, and cytoplasm. 5. Clean the slide and coverslip, and WASH YOUR HANDS! ONION CELLS Initials Magnification Part C Cells of a Leaf Although most cells of plants and animals are similar in structure, there are a few major differences. In this investigation, you will observe these differences under the microscope. Procedure and Observations Prepare a wet mount of an Anacharis leaf. The whole leaf should be used. Examine the leaf under the low power of the microscope. Then select a portion of the leaf where the cells are particularly distinct. Center this portion in the microscope field. Bring it into focus under high power. Use the fine adjustment to observe the cells at various depths. Draw some cells of an Anacharis leaf. Label your drawing, indicating the cell wall, cell membrane, chloroplasts, and cytoplasm. Initials Magnification 3

4 Part D - Cell Membrane and Cytoplasm Human cheek cells can be used for looking at the plasma membrane and cytoplasm. 1. Put a drop of iodine on the slide. If you spill the iodine, wash with water immediately and tell the teacher. Gently scrape the inside of your mouth with a toothpick. You should not be able to see anything on the toothpick when you take it out of your mouth! 2. Put the toothpick into the stain on the slide and mix it around once or twice. Place the toothpick in the garbage immediately NOT back in your mouth! 3. Put on the cover slip and look at the cells under low and high power. 4. Look at the cells that are by themselves, not the ones that are all clumped together. 5. Draw several individual cheek cells under high power. Label the cytoplasm, nucleus, and the plasma membrane. Clean the slide and cover slip. CHEEK CELLS Initials Magnification Analysis Part A 1. Fill in the chart below to show the total magnification of your microscope on low power and high power. To find the total magnification, multiply the eyepiece and objective magnifications. EYEPIECE OBJECTIVE TOTAL MAGNIFICATION What is the magnification of the low power objective on your microscope? 4

5 3. Describe some of the differences between what the e looks like under low and high power. 4. Is the field of view brighter or darker under the high power? Part B 1. Describe the shape of the onion cell. 2. What does the cell wall do in the onion cell? 3. Use your book to describe the job of the nucleus. Part C 1. Describe the shape of the Anacharis leaf cells. 2. What is the function of the chloroplasts?. Part D 1. Describe the shape of the cheek cell and how this shape is so different from the leaf cell that you looked at previously. 2. Compare the shape of the nucleus in the cheek and the onion cell. 5

6 3. Are cheek cells produced by plants or animals? How do you know? 4. Use your notes to describe the job of the plasma membrane. 5. What does the cytoplasm do in the cheek cell? 6. Why did you add stain to the cheek cells? Analysis General Complete the following chart. Put an X in the box if the structure is found in the plant or animal cell. Animal Cell Plant Cell NUCLEUS CELL WALL CYTOPLASM NUCLEAR MEMBRANE CELL MEMBRANE Conclusions: 1. If you were given a cell that was unidentified, how could you determine if it was a plant or animal cell? Be specific in what you would look for in each type of cell. 3. How should you carry a microscope? 4. Why should you only use lens paper to clean a lens? Why can t you just use a paper towel? 6