Cell Structure and Diversity


Upon completion of this lab, you should be able to


In this laboratory investigation, you will have the opportunity to visualize several different types of plant, animal, and protistan cells and organisms. As you view them, try to keep in mind that, whether they are unicellular or multicellular, organisms all have the same basic problems to solve. They also have many of the same cellular structures to carry out their life functions.

As you view the slides, try to think about the various cell structures that these cells have in common

  1. Elodea leaves and cells: Use the embedded links to show both low and high powers (100X, 400X) and find individual cells. The circular green structures around the edge of the cell are chloroplasts, which contain chlorophyll for the process of photosynthesis. As this animation shows, as the molecules move, the cytoplasm will begin to flow around the edge of the cell, and the chloroplasts will move with it. It will look like little green circular cars moving around the edge of the cell. This process of cytoplasmic movement is known as CYCLOSIS. Note any structures other than the chloroplasts that are part of the individual cells. Here are some additional links that show cyclosis and cellular structure.    

    Link 1
    Link 2
    Link 3

  2. Spirogyra (green algae): This common algae is found in ponds and carries on photosynthesis. It is also a source of food for animal organisms in the pond or stream. Look at the cell arrangement: a long string of cells attached end to end. This arrangement is known as a FILAMENT. Note the shape of the chloroplast and any other cellular details.

  3. Zygnema: This filamentous alga is often found with Spirogyra, floating at the top of still or stagnant bodies of water. Zygnema have two distinctive star-shaped chloroplasts per cell, which make them easy to identify under the microscope. Like Spirogyra, Zygnema serve as food sources for water organisms and often exist as tangled green or yellow-brown mats.

  4. Euglena: These protists have features of both plant and animal organisms. They are very small and can direct their own movement by means of a whiplike appendage called a FLAGELLUM, which is located at the front end of the cell. The flagellum will probably be difficult to see. You may be able to see a small orange or red spot near the base of the flagellum. This mass of pigment materials senses light and helps the organism remain near sunlight so it can carry on photosynthesis See if you can find the chloroplasts. You should be able to see the nucleus.

  5. Paramecium caudatum: This animal-like protist has a slipper-like body structure. It moves by mean of CILIA, which are a short version of the flagellum. You may see the effect of their movement as the organism moves through the water. Food is taken in through a channel called the oral groove, which may show up as a roundish, dented area in the cell. This organism has two nuclei, a large macronucleus and a smaller micronucleus. Paramecium gets rid of excess water through a structure called the CONTRACTILE VACUOLE.

    This link has a number of Quick Time movies of different protozoans.

  6. Allium (onion): This link will provide you with a number of pictures of the onion skin taken at both low and high power. Also visit the website of Steve Durr, who is mentioned at the bottom of the onion site, and note many of the organisms previously seen.

  7. Trypanosoma: These slides are of blood, so most of what you will see are blood cells. Scattered throughout the slide will be squiggly-looking cells. These organisms are parasitic protozans that are spread by tsetse flies and various beetles and cause African Sleeping sickness and other neurological disorders. Note the cell structure. The flagellum runs along the long side of the cell and is connected on the surface to the membrane that acts like a fin. The nucleus will be near the center of the cell, and there may be a dark structure near the front of the cell where the flagellum is attached.

  8. Blood slides: Human and other animal blood slides are available for viewing. The red blood cells are small and may have a light orange-red to brown color. There are several larger and more colorful cells scattered among the red blood cells. These are the white blood cells. In humans, there are five different types of white blood cells. See how many different types you can find in both human and other animal blood cell slides.

    1000X magnification of fish blood - white blood cell is a lymphocyte

    1000X magnification of fish blood - white blood cell is a basophil that contains lysosomal granules and is thus called a granulocyte

    Low power view of frog blood

    Phase contrast view of frog blood cells

    Site that explains all types of blood cells

    Low power view of human blood cells. White blood cells have prominent purple nucleus.

    High power view of human blood cells

    Highly magnified view

Great Starting Point for Plants, Fungi, Protista, Animals

Introduction to the Fungi

Part I
Fungi are eukaryotic organisms that lack the ability to carry on photosynthesis. Their nutritional modes reflect this fact. Their main role in nature is to act, along with the bacteria, as decomposers. Their external digestion of substrate materials allows them to breakdown or degrade organic materials. These materials can then be absorbed back into the fungi or into other plants. It is thought that most (over 80%) of plants have fungi that live in or around their roots. These fungi are known as MYCORRHIZAE.

Dependent on growth conditions, fungi exist as single cells known as YEAST or as threadlike tubular strands of cells called hyphae. Some of these hyphae ascend and support the spore producing structure. Fungi are classified into groups on the basis of their sexual reproductive structure, or lack of one. Other hyphae descend into the substrate and anchor and absorb materials for the fungi, acting in some ways like roots. The total mass of the hyphae make up the body of the moldlike fungus known as the MYCELIUM.

Four groups are currently recognized:

  1. Zygomycota - contains the bread mold; most common is Rhizopus
  2. Ascomycota - sexual structure is called the ascus and usually contains 8 spores; contains single-celled yeasts such as Saccharomyces and multicelled morels and truffles; there are some important parasitic members as well
  3. Basidiomycota - sexual structure is the basidium which hangs down from the cap of the familiar mushrooms; also important parasites in this group
  4. Deuteromycota - sometimes known as the Imperfect Fungi because we have not identified a sexual reproductive structure yet; ringworm causing organisms as well as Penicillium and Aspergillus are in this group

A fifth group, the Lichens, are usually studied with the fungi. Lichens represent an organism created as the result of an apparent mutualistic relationship between a fungus and a photosynthetic partner. The photosynthetic partner may be an alga or a cyanobacterium. The body plan of the lichen resembles that of a leaf with the fungi in the place of the upper and lower epidermis and the photosynthetic partner in the area of the palisade cells.

Part II
Follow these links for a fun way to grow your own fungi at home. There are a number of factors, both physical and chemical that can easily be tested at home. Try two or three of these.

  1. the effects of temperature on fungi - put bread and a moist paper towel in a boilable plastic bag and microwave for two minutes. Be sure paper is still moist. Prepare a second slice and moist towel but omit the microwave step. Incubate at room temperature and record time of first growth and which type of bread.
  2. the effects of salt - use moist towel, bread and salt the surface of one piece of bread but not the control. Incubate at room temperature and compare results.
  3. dry bread versus moist bread
  4. bread made with preservative and without
  5. the effects of sugar or sugar substitutes on fungal growth
Assignment for Diversity Laboratory Investigation

Assignment for Diversity Laboratory Investigation


1. List 5 reasons why lichens are important.

          Hint: Go to http://ocid.nacse.org/lichenland/ and view

                   the first and third boxes


2, List 10 reasons why fungi are important. Try to include examples from

    each fungal group. Get at least three examples from the Ascomycetes



          Hint: Try the following links to find some answers





3. Why do fungi deserve their own kingdom?


4. Distinguish between and explain the following types of movement

    exhibited by cells? Give examples of specific organisms associated with

    each type of movement.

          Brownian movement                      Cyclosis

          Ameboid motion                              Self directed movement



Here is another source of information and lab possibilities for fungi.








Kingdom Fungi courtesy of Ohio State
Everything you would ever want to know about yeast
Yeast Images
Everything you would ever want to know about lichens.