1. Mitosis Lab Ocular lens - 10X Objectives - 4X - 40X
Total Magnification
x 10X = 40X
x 10X = 100X
x 10X = 400X
Diaphragm – adjusts light & heat
How to use the microscope
Turn on – crank dial to 10
Adjust light with diaphragm
Place slide in corner & release
retractable arm….gently!!!!!!
Using scanning lens (4X), focus
on sample with coarse focus
Change objective (if needed)
Repeat

2. Mitosis Lab

3. Mitosis Lab
Figure 12.10

4. Mitosis Lab Prophase Metaphase Anaphase Telophase = 25 cells
If your observations had not been restricted to the area of the root tip that is actively dividing, how would your results have been different?
Why did we choose to use the onion root tip to study mitosis?
Calculate the percentage of cells in each stage. Consider that it takes (on average) 24 hours (1440 min) for onion roots tip cells to complete the cell cycle. Knowing this, you can calculate the amount of time spent in each phase of the cell cycle from the percentage of cells found in each stage of mitosis. (Recall 90% of time is spent in interphase.)
% of cells in stage X min = _____ minutes in that stage
(mitotic phase)
Draw an example of each stage.