Students should be able to...
identify the various cell organelles either from a model or in the field of view of the microscope
define the basic function of each cell organelle
describe technique for creating a wet mount slide
define the three type of tonicities and the effects each tonicity has on a cell
identify the various stages and phases of mitosis
I. Cell Model: Learn and identify on a cell model the following cellular regions and various organelles. Cell Model 1, Cell Model 2
|Plasma membrane (cell membrane)||phospholipid bi-layer that surrounds the cell and controls movement of particles into and out of the cell|
|Cytoplasm||fluid component in which the organelles are suspended|
|Nucleus||control center of the cell and contains genetic material (DNA/RNA)|
|Nucleolus||site of rapid RNA production|
|Endoplasmic Reticulum (ER)||rough ER - site of protein synthesis
smooth ER - site lipid and carbohydrate synthesis
|Ribosomes||non-membranous organelle located within the rough ER and is the actual site of protein synthesis|
|Golgi apparatus (body)||processing, packaging, and distribution of substances made by the ER|
|Mitochondria||site of ATP synthesis|
|Lysosomes||vesicle that contains hydrolytic enzymes|
|Centrioles (Centrosome)||non-membranous organelle that forms mitotic spindle fibers|
|Vesicles (vacuole)||liquid-filled sac used for storage of various organic and inorganic compounds|
II. Cheek cell preparation: be able to recognize each of the cell structures apparent on a wet mount of cheek cells.
1. Prepare your own slide by gently scraping your own inner cheek lining with a toothpick or wooden applicator stick.
2. Smear the moist substance in the center of a clean glass microscope slide.
3. Flood the smear with 1 drop of the methylene blue stain provided.
4. Gentle place a coverslip on top of the stain.
8. Place on the stage platform.
9. Observe with the microscope, beginning with the scanning power.
10.Recognize structures evident in the cheek cell preparation: Picture
a. nucleus/nuclear membrane
c. cell membrane
d. food debris and/or bacteria
11.Dispose of the slide in a container of chlorine-based bleach as indicated by the instructor or by placing the slide into a glass disposal box.
III. Cell physiology demonstration:
A. Osmosis and diffusion:
The instructor will demonstrate by video-micrograph the response of fresh, living red blood cells to solutions of various concentrations.
attention to the instructor's comments about the use of fresh blood in an
2. Predict results of osmosis in solutions of different concentrations. Picture
a. isotonic (same solute concentration as cell contents): no visible change in the cell
b. hypotonic (less solute concentration than cell contents): water gain resulting in swelling and potentially lysis of cell (hemolysis)
c. hypertonic (more solute concentration than cell contents): water loss resulting in crenation
Study prepared slides from the
whitefish blastula in order to become familiar with a typical cell during its
reproductive process. The term "blastula" refers to a sphere of
rapidly dividing embryonic cells. The whitefish produces good examples of cells
undergoing mitosis, as they are large and easy to obtain and manipulate.
You will be given a slide which has about 30 pink dots on it visible to your
unaided eye. Each one of those pink dots, upon examination with the
microscope, will show 20-50 cells. These cells are stained with a dye
which causes the cytoplasm to appear pink and nuclear material to appear purple.
Since each dot represents a slice through a 3-dimensional sphere of cells (the
blastula), each cell will not be sliced directly through its axis. Many
cells will not show a recognizable structure. Ignore those. Scan
around for cells which are cut in such a way that typical mitotic figures
(appearances of typical stages of the process) are evident. Use the
photomicrographs in your text, your lab atlas, or attached as links to
let you know what to look for.
1. Recognize various stages of the cell cycle:
2. Recognize significant structures associated with the process of mitosis:
- spindle fibers (apparatus)
IV. Useful Websites
Jerry G. Johnson - good quiz over body organization for both lecture and lab
University of Minnesota- good quizzes over cell parts
North Harris College - interactive quiz on tonicity and its effects on blood cells
Terry Brown - animated osmosis overview
Rodney F. Boyer - cell transport animation
North Harris Community College - mitosis tutorial
North Harris College - diffusion and osmosis tutorial