Objectives/Procedure
The goal of this experiment was to identify the different stages of mitosis through viewing two prepared slides of an onion root tip and a whitefish blastula under 400X, using a light microscope.
Mr. Wong had to help us to get started as we were having trouble focusing the microscope on the slide in order to clearly visualize the chromosomes. He took a great first picture of the slide whitefish blastula (below).
Then, we proceeded to the onion; reading the lab activity, we discovered that growth especially took place at the root tips, containing meristematic tissue.
Results
Cells were determined to be in one of the four stages of mitosis (prophase, metaphase, anaphase, telophase) or interphase. Finally, the results were compiled into a table, in order to calculate the amount of time cells spend in each phase.
131 cells were thought to be in interphase; 75 in prophase, 29 in metaphase, 13 in anaphase, and 18 in telophase with all 267 cells being counted in both fields of view. 720 minutes in interphase, 403.2 for prophase, 158. 4 in metaphase, 57.6 minutes in anaphase, and 100.8 minutes in telophase was derived from the results under field 1 and field 2 columns.
The formula used to derive the calculations for time spent in each phase was the following:
% of total cells counted * 1440 minutes (equivalent to 1 day) = time in each stage
Since field two consisted of the onion root tip, more cells were in mitosis thus affecting the lab calculations. Additionally, human error in counting and incorrect distinguishing between stages in the cell cycle (like interphase and prophase) also affected the calculations.
Attached below is the link to the Mitosis Lab Handout, which is completed (see the last 2 pages, 6 and 7).
Aditya's Bio Blog 