Follow the procedures listed to conduct three experiments:
Experiment 1: Mitosis in Onion Root Cells
Experiment 2: Mitosis in a Whitefish Blastula
Experiment 3: Live Mitosis in Cultured Mammalian Cells
Fill out the worksheet, in the document itself, as you complete the experiments.
Experiment 1: Mitosis in Onion Root Cells
Part 1: Stages of Mitosis
Take a microscope from the Instruments shelf and place it onto the workbench.
Take an onion root slide from the Containers shelf and place it onto the microscope stage. Use different objectives and focus until you can clearly see many cells in one view.
Scan through the slide using the x-axis stage adjust and y-axis stage adjust knobs and find at least one cell in each stage of the cell cycle:
Interphase
Prophase
Metaphase
Anaphase
Telophase
Label images of the specific cell phases. To do so, use the overlay tools at the top of the microscope’s viewscreen.
Your annotated images should look something like Figure 20.04.
Figure 20.04 An Example of Onion Root Cells Labeled with Their Phase of Mitosis (Macmillan Learning)
Save a screenshot of each annotated image to upload and submit it later.
Part 2: Relative Time Spent in Mitosis
Select one side of the root tip. Scan 5 columns across and 20 cells down within each column. Identify the phase that each cell is in, to the best of your understanding. Use initials for the phases:
I = Interphase
P = Prophase
M = Metaphase
A = Anaphase
T = Telophase
Record a grid of cells that looks something like this to reference later:
| I | M | I | I | I |
| I | I | I | I | A |
| I | I | I | P | I |
| I | I | I | I | I |
| T | I | I | I | I |
Determine the number of cells in each stage of mitosis by counting every incidence of its corresponding letter. For example, add all letter I’s to determine the number of cells in interphase, and so on for each stage. Record this information.
When you are finished, drag the slide back to the Containers shelf.
Experiment 2: Mitosis in a Whitefish Blastula
The cells of a blastula, or developing embryo, divide rapidly, which make this whitefish slide useful for viewing the different stages of mitosis.
Take a whitefish blastula slide from the Containers shelf and place it onto the microscope stage. Make the necessary adjustments to focus in on the cells.
Find at least one cell in this fish embryo to represent each of the phases below.
Interphase
Prophase
Metaphase
Anaphase
Telophase
Label your images of the specific cell phases. To do so, use the overlay tools at the top of the microscope’s viewscreen. Take a screenshot of each annotated image to upload and submit it later.
Experiment 3: Live Mitosis in Cultured Mammalian Cells
Watch the Mitosis video to see how the process of mitosis unfolds in the live cell. How does it compare to the static images in the microscope slides? Record your observations to reference later.
Clear the bench of all slides and instruments by dragging them back to the shelves, and then return to your course page to complete any assignment for this lab.
