Docstoc

Cell Lab - Midway ISD

Document Sample
Cell Lab - Midway ISD Powered By Docstoc
					                                          The Basic Unit of Life

                                             Cell Lab Set Up

On page 1:

   -   Write your full heading in pencil (Name, Period and Date)
   -   Write the lab title in the center of the page
   -   Skip a line and write the word “Objectives” in the left column. State the objectives from the lab.
   -   Skip a line and write “Procedure” in the left column. Skip a line and write “Part A: The Cell Wall”
       in the left column.
   -   Skip two lines. In the center of the page, use your pencil and trace the cup as your template to
       draw a field of view. *Be sure to leave room for a title on top, magnification on the bottom and
       labels on the right.
   -   Skip two lines and write “Analysis: Part A”. You will answer 7 questions here, using complete
       sentences that restate the question. Leave about 21 lines for the questions. Do not prenumber.

On page 2:

   -   Write “Part B: Cell Membrane and Cytoplasm” in the left column.
   -   Skip a line. In the center of the page, use your pencil and trace the cup as your template to
       draw a field of view. *Be sure to leave room for a title on top, magnification on the bottom and
       labels on the right.
   -   Skip two lines and write “Analysis: Part B”. You will answer 9 questions here, using complete
       sentences that restate the question. Leave about 27 lines for the questions. Do not prenumber.

On page 3:

   -   Write “Part C: Cell Nucleus and Nucleolus” in the left column.
   -   Skip a line. In the center of the page, use your pencil and trace the cup as your template to
       draw a field of view. *Be sure to leave room for a title on top, magnification on the bottom and
       labels on the right.
   -   Skip two lines and write “Analysis: Part C”. You will answer 8 questions here, using complete
       sentences that restate the question. Leave about 24 lines for the questions. Do not prenumber.



Lab Drawing Checklist:

   -   Title
   -   Template (traced circle cup)
   -   Magnification
   -   Accuracy of drawing
   -   Color
   -   Labels (on the right, horizontal lines using a ruler, no underlines)
                                               The Basic Unit of Life

Introduction: When different types of cells are viewed under a microscope, different cell parts can be
seen. Certain living cells are best for showing parts like a nucleus or cell membrane. Once living
(preserved) cells are best for showing parts like a cell wall. Cells from producer organisms (plants) will
show parts such as chloroplasts and cell walls. Most consumer organism cells do not have these parts,
although fungi have cell walls. We will not consider fungi in this investigation.

Objectives: In this investigation, you will:

    (a) Observe a variety of living and once living materials under the microscope
    (b) Determine if these materials do or do not show a cellular type of organization
    (c) Study and locate under the microscope five specific cell parts- cell wall, cell membrane,
        cytoplasm, nucleus, nucleolus and chloroplasts
    (d) Compare the cell parts found in plant and animal cells



Materials

    -   Microscope
    -   Microscope slides
    -   Coverslips
    -   Dropper
    -   Cork prepared slide
    -   Water
    -   Toothpicks
    -   Methylene blue stain
    -   Onion
    -   Iodine stain



Procedure

Part A: The Cell Wall

Cork cells are excellent for studying a cell part common to all plant cells. This part is the cell wall. In a
cork cell, the cell wall is easily visible. The cork is no longer living. The cell wall remains as the only
evidence of once living materials

    1. Obtain a prepared slide of cork.
    2. Examine the cork under the low power first to get it focused. Then move through medium
       power to high power.
    3. In your field of view, draw the cork cells as they appear in high power. LABEL the CELL WALL.
           a. Be sure to follow directions for labeling all aspects of the drawing.
Analysis Part A:

    1.   Is the cork you used alive?
    2.   What are the small units that can be seen called?
    3.   Do these units appear to be filled or empty?
    4.   What specific part is all that remains of the cell?
    5.   In 1665, Robert Hooke, an English scientist, reported an interesting observation while looking
         through his microscope at cork. “I took a good clear piece of cork, and with a penknife
         sharpened as keen as a razor, I cut a piece of it off, then examining it with a microscope, me
         thought I could perceive it to appear a little porous, much like honeycomb, but that the pores
         were not regular.”
              a. What were the honeycomb units at which Hooke was looking?
              b. What specific part of the cell was all that was left to see in Hooke’s microscope?
    6.
             a. Is cork produced by a plant or an animal?
             b. Do animal cells have cell walls?



Part B: Cell Membrane and Cytoplasm

Human cheek cells may be used for viewing the cell membrane and cytoplasm. A cell membrane is a thin
outer boundary which surrounds the cell and separates it from neighboring cells. Cytoplasm is the
jellylike inner portion of the cell.

    1. Obtain a microscope slide, a coverslip and a toothpick.
    2. Gently scrape the inside of your cheek with the end of a toothpick. You will not be able to see
       anything on the toothpick when you remove from your mouth.
    3. Place a drop of methylene blue stain and a drop of water onto a slide.
    4. Roll your toothpick end into the stain on the slide and swirl it around.
    5. Add the coverslip and wick away an excess liquid using a paper towel.
    6. Place the slide on your microscope and examine under low power to focus and then through
       medium and into high power.
       *Try to find cells that are separated from one another instead those in clumps.
    7. In your field of view, draw several cheek cells as they appear under high power. LABEL the CELL
       MEMBRANE and CYTOPLASM.




Analysis Part B:

    1. Describe the shape of the cheek cell.
    2.
           a. Are cheek cells produced by plants or animals?
           b. Is a cell wall present?
    3. Are cheek cells alive?
    4. Where in the cell is the cell membrane found?
    5. What is the function of the cell membrane? (Use your textbook if necessary.)
    6.
            a. Where in the cell is the cell’s cytoplasm found?
            b. What does the cytoplasm look like?
    7. What is the function of the cell’s cytoplasm? (Use your textbook if necessary.)
    8. Why was a stain added to the cheek cells?
    9. Do you have evidence that living things (or once living things) are composed of basic units called
       cells?



Part C: Cell Nucleus and Nucleolus

Onion cells may be used to show a cell’s nucleus and nucleolus. These two structures appear within
most living cells. There may be several nucleoli appearing as tiny dots within each cell’s nucleus. The
nucleus will appear as a round structure inside each cell.

    1. Obtain a small piece of onion and use your fingernail to peel off a thin layer of onion tissue.
    2. Place the onion layer onto a microscope slide. Make sure the onion is relatively flat.
    3. Add one drop of iodine on top of the onion and place a coverslip over the top.
    4. Observe the cells under low power, then medium and high power. Note the brick wall
       appearance of the cells with cell walls separating the cells.
    5. Locate a small round structure, the nucleus, within each cell.
    6. In your field of view, draw the onion cells as they appear under high power. LABEL the CELL
       WALL, NUCLEUS, NUCLEOLUS, and NUCLEAR MEMBRANE.



Analysis Part C:

    1. Describe the shape of an onion cell.
    2.
          a. Are onion cells produced by plants or animals?
          b. Is a cell wall present?
    3.
          a. Describe the shape of the nucleus of an onion cell?
          b. What structure surrounds the nucleus?
    4. What is the function of a cell’s nucleus? (Use your textbook if necessary.)
    5.
          a. Describe the shape of the nucleolus of the onion cell.
          b. Where is the nucleolus found in the cell?
    6. What is the function of the cell’s nucleolus? (Use your textbook if necessary.)
    7. What structure separates the contents of the nucleus from the cytoplasm?
    8. Why were the cells stained?

				
DOCUMENT INFO
Shared By:
Categories:
Tags:
Stats:
views:17
posted:11/11/2011
language:English
pages:4