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Purpose:
To provide the students with the opportunity to learn the different stages of cellular and nuclear replication that occur in mitosis of plant and animal cells. In addition, the students will be making slides of onion root tips and calculating the relative duration of the phases of mitosis in the meristem of root tissue. Students will also be comparing and contrasting the stages of mitosis in plant and animal cells.
Summary:
Microscopic examinations of prepared slides and fixing and staining of slides. The students will use the information gained to answer questions.
Objectives Links:
Cell Cycle and Its Regulation
Meiosis and Gametogenesis
Process Skills Checklist
Materials:
Per group (3-4 students):
- 1 prepared slide of whitefish blastula mitosis
- 1 prepared slide of onion root tip mitosis (longitudinal sections)
- pear onion bulbs
- slides and cover slips
- Bunsen or alcohol burner
- slide holder
- several paper towels
- razor blades
- compound light microscopes
- lens cleaning paper
- 0.5% toluidine blue (in dropper bottle)
- 1 M HCl (in dropper bottle)
Safety Concerns:
The teacher should review the following with all students taking part in this laboratory exercise:
- Since the students will be using toluidine blue solution and HCl during this laboratory exercise, the instructor should review basic safety precautions pertaining to the use of these chemicals. Students and instructor should use caution when handling HCl and toluidine blue and avoid contact with eyes, skin, and clothing. Both solutions can burn the skin and damage (cause stains and/or holes) in clothing.
- Since an open flame is used in this lab, the instructor should review students on how to handle the Bunsen burners and what to do in case of fire or burns.
- Instruct students to wear a lab apron and their safety goggles or glasses at all times during this laboratory exercise.
- Remind students that they should perform only the procedures described in the student directions and only under the supervision of the teacher.
- Remind students that should an accident occur during this laboratory exercise, the student should stop work immediately and notify the teacher.
Revision Date:
Summer 2001
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