Mitosis - Internet Lesson KEY

In this internet lesson, you will review the steps of mitosis and meiosis and view video simulations of cell division. You will also view an onion root tip and calculate the percentage of cells at each of the stages of cell division .

Mitosis Tutorial at

On the left side of the screen is a navigation bar, click on the link to “MITOSIS” Read the text on this page and view the animation, you can slow down the video by clicking step by step through the phases.

1. Which stage does the following occur:
Chromatin condenses into chromosomes - prophase
Chromosomes align in center of cell. - metaphase
Longest part of the cell cycle. - interphase
Nuclear envelope breaks down. - prophase
Cell is cleaved into two new daughter cells. - telophase (cytokinesis)
Daughter chromosomes arrive at the poles - telophase
Chromatids are pulled apart - anaphase

Watch the video carefully.

2. The colored chromosomes represent chromatids. There are two of each color because one is an exact duplicate of the other.-How many chromosomes are visible at the beginning of mitosis? _____4_____
--The little green T shaped things on the cell are: ___centrioles________________
-- What happens to the centrioles during mitosis? __move to the poles_________________

3. Identify the stages of these cells:


mitosis telophase



Another Mitosis Animation

Go to and click on the mitosis animation.










Onion Root Tip

Online Activity at

Read the introduction, then click the “next” button.

You will have 36 cells to classify. When you’re finished, record your data in the chart below.

  Interphase Prophase Metaphase Anaphase Telophase Total
Number of Cells 20 10 3 2 1 36
Percent of Cells (calculate: number of cells divided by total cells x 100) 56% 28% 8% 6% 3% 101%*

due to rounding of numbers, 101% is the total for percentages

Mitosis in Whitefish & Onion Roots

For each organism, identify the stage of mitosis.

View 1
View 2
View 3
View 4
View 5
Whitefish anaphase metaphase prophase telophase -
Onion anaphase metaphase interphase cytokinesis telophase