What role does mitosis play in the growth of an embryo?

Experiment Mitosis
Lab RepoRt assistant
This document is not meant to be a substitute for a formal laboratory report. The Lab Report
Assistant is simply a summary of the experiment’s questions, diagrams if needed, and data tables
that should be addressed in a formal lab report. The intent is to facilitate student’s writing of lab
reports by providing this information in an editable file which can be sent to an instructor

Mitosis Worksheet – Answer the questions about the photos below:
Onion root tip photos at 600X and 1000X taken by Stan Carpenter of Hands-On Labs, Inc.

1. What phase is this cell undergoing?

1. The two center side-by-side cells are
undergoing two different phases of
a. What are these phases?

2. What happens after this phase?

b. What diagnostic features can help
you with your decision?

1. What phase is this cell undergoing?

1. This cell has clearly visible chromatids.
a. What’s the next phase this cell will

2. How can you tell?

b. Where will the chromatids go in the
coming phase?

1. The cell in the lower center is exhibiting signs 1. Explain what happens during anaphase.
of what phase of mitosis?

2. What phase does it appear the cell above is
2. When the chromatids separate, what is
each called?

A. What is the purpose of mitosis?

B. Why is the cell cycle important for organisms?

C. What role does mitosis play in the growth of an embryo?

D. What is one main difference in the mitotic processes between plant and animal cells?

E. If the cell that has undergone mitosis originally had the diploid (2n) number of chromosomes,
then what number of chromosomes will the nuclei in the two new cells have?

F. Can mitosis ever be used for reproduction?

G. What parts of plants are most impacted by mitosis?

H. Why might mitosis be easier to study in the tip of the root?

I. Where else in a plant might you find a large amount of mitotic cell division occurring?

J. How might the mitotic index be applied in agriculture?

K. What did you compute to be the mitotic index of the combined six slides (assume there are
54 total cells)? In comparison to the indexes reflected in Figure 8, from approximately which area
of a root was the sample taken?