• Mitotic cycle
• The role of Chromosomes in heredity
• Comparison of plant and animal cells

Today you will use prepared slides to investigate the phases of mitosis in both plants and animals.

• Longitudinal sections of the root of Allium, will be used to examine the cells in the root meristem, the growing region of the root.
• Whole mounts of whitefish blastula will illustrate reproductive cells in animals. These undifferentiated cells undergo mitosis at a regular interval as the embryo increases in number of cells and complexity.
• You will make observational drawings and be prepared to take a practical quiz.

Standards:

High School:

Cell Biology

1. The fundamental life processes of plants and animals depend on a variety of chemical reactions that occur in specialized areas of the organism's cells. As a basis for understanding this concept:

c.

Students know how prokaryotic cells, eukaryotic cells (including those from plants and animals), and viruses differ in complexity and general structure.

Middle School:

Cell Biology

1. All living organisms are composed of cells, from just one to many trillions, whose details usually are visible only through a microscope. As a basis for understanding this concept:

b.	Students know the characteristics that distinguish plant cells from animal cells, including chloroplasts and cell walls.
c.	Students know the nucleus is the repository for genetic information in plant and animal cells.
e.	Students know cells divide to increase their numbers through a process of mitosis, which results in two daughter cells with identical sets of chromosomes.
f.	Students know that as multicellular organisms develop, their cells differentiate.

Study Guide:

Plant and Animal Mitosis

Your objective:

Find and make observations of cells in each phase of mitosis in plant and animal tissue. Compare the differences between plant and animal mitosis. Be able to correctly identify the phases from both plant and animal tissue.

Materials:

• Prepared slide labeled 'Allium root, mitosis'
• Prepared slide labeled 'whitefish blastula, mitosis'
• compound microscope

Procedures:

• Set up your microscope, place the onion root slide on the stage and focus on low (40x) power.
• move your slide so that your field of view is centered on the root tip.
• Focus at 100x and re center so that you are focused on the more 'square' meristem cells.
• Focus at 400x.
• Slowly move the slide and search for cells in each phase of mitosis
• When you have found one, make a detailed observational drawing of that cell. Label all important structures (nucleus, chromosome, cell plate). Title the drawing with the type of cell, magnification, and phase of mitosis.
• Continue with your observations until you have found cells in each phase and both you and your partner can easily identify each phase.
• Remove the onion root slide and replace it with the whitefish blastula slide. Focus and center at 40x, 100x, and 400x magnification.
• As instructed above, locate and make observational drawings of each phase of mitosis.
• Answer the questions below and then let your instructor know you are ready for your practical quiz.

Questions:

1. Which cells (plat or animal) shows the most regularity in the direction in which it divides? Give an explanation for this difference.
2. What evidence of cytokinesis is visible in telophase in the onion root cells? Do you have this evidence in your drawing?
3. What evidence of cytokinesis is visible in telophase in the whitefish cells? Do you have this evidence in your drawing?

References & Links:

Cells Alive: mitosis animation

University of Arizona Tutorial

Stephen Wolniak, U. of Maryland. Tutorial with high magnification photos