MITOTIC INDEX
Mitosis – Cell Cycle.pdf worksheet Instructions:
You will probably need me to explain this worksheet read the notes below that explain the activity in the worksheet. What you are going to do is count all of the cells in the field of view of microscope. All this means is that you count all of the cells in your picture which represents what you see in a microscope if you were looking at cells.
A) Using your understanding of Interphase and all of the phases of mitosis you will categorize each cell as either:
Interphase, Prophase, Metaphase, Anaphase, telophase, and cytokinesis. If you have to look at your textbook to review these phases is on page 232 – 234.
B) Once you have categorized each cell then complete the math to determine the mitotic index. This is just the fraction or decimal value:
The total number of cells in Mitosis/Total number of cells
The total time in the phase uses the assumption that there is a 24 hour life cycle of these cells. to calculate that calculate the percentage of cells in each phase/ total cells and multiply by 24 hours.
See the video for explanation. It is really easy.
Let me give you an example:
The picture below represents a field of view in microscope of onion root tip cells undergoing mitosis. From this picture, count and categorize each visible phase of mitosis. Remember that Interphase is when the cells are not in Mitosis.
You may disagree with a couple or a few of my cells in some of the categories. You are not wrong to question me! In fact you should always question your teacher! Considering Prophase starts with “visible chromosomes” condensing one could argue cell #14 is in prophase and you would not be wrong. I think cell #14 does not show individual chromosomes yet but neither of us are wrong, just a difference of opinion. Remember there is really no beginning or end of these phases. It a continuum. Only us humans try to define this. The cell is busy duplicating and does not care! So if you have a few cells in different categories that are different from me and have a valid explanation then it is perfectly fine. Doesn’t Early Prophase looks like late Interphase?
After you have tried the worksheet using my notes above, please view the video below and the key below to review.
Mitosis Cell Cycle worksheet review: This is for the homework form below..
This will help in identifying the phases and chromosomal line of inheritance.