Mitosis Lab
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For the second term formal lab report you will be completing a lab exercise about mitosis and researching
information about different types of cells. Prior to the actual lab work you will prepare a pre-lab (as outlined below).
After your work in the lab you will revise and add to the pre-lab to make it a formal lab report. Some things to keep
in mind:
1. Most importantly … FOLLOW DIRECTIONS!
2. You are encouraged to seek extra help from me with writing both the pre-lab and formal lab. However, you
need to plan your time and not wait for the last minute to complete the work. Therefore, you may not ask
questions about the pre-lab or formal lab after 3pm the day before it is due.
3. Your pre-lab is due (printed BEFORE you get to class) the day you do the lab exercise.
a. Blue class – Monday, February 10th (last questions by 3pm on Friday, February 7th )
b. Green class – Wednesday, February 12th (last questions by 3pm on Tuesday, February 11th )
4. This document (the one you are reading right now!) must be attached to your pre-lab.
5. Your formal lab report is due (printed BEFORE you get to class) along with your ORIGINAL GRADED pre-lab:
a. Blue class – Tuesday, February 25th (last questions by 3pm on Monday, February 24th )
b. Green class – Thursday, February 27th (last questions by 3pm on Wednesday, February 26th )
6. The original graded pre-lab (along with this document) must be resubmitted with the formal lab report.
7. Read through this entire handout before trying to answer any of the questions.
8. The procedure for the lab activity is as follows. It is not in your lab manual.
Procedure:
You will follow the following procedure during the lab – so make sure you have this with you on lab day!
1. ___Focus the microscope on the slide of onion root tips under low power
2. ___Focus the microscope on medium and then high power (using only fine adjustment)
3.
___Find a section near the end of the root tip where there are LOTS of cells in different phases of mitosis.
(the end of the root that you want comes to a point)
4. ___Ask your teacher to check the position and focus (Do not move to step 5 without approval)
5. ___Complete the table in this handout with your detailed illustrations of each cell stage under the
microscope. Make sure to draw what you actually see and not what you think you are supposed to see.
Pre-lab Requirements:


Cover Page (completed)
Introduction (completed)
o
o
o
o




Explain how the topic is related to the real world. You might consider learning about different types
of cells and when and why they divide. Cite information from your textbook AND at least one
outside source (NOT an encyclopedia). You must use parenthetical references.
Include definitions of relevant terms (in sentence form).
Briefly state the purpose of the experiment.
Write the claim and your rationale (from Question # 4 in the “Additional Questions” below) – but DO
NOT use first person.
You will NOT have the following sections:
o Materials
o Procedures
o Results
Additional Questions (see below)
Conclusion – you will need this heading, but no information under the heading.
References – Use APA citation (discussed in class and on my Teacher Page) for:
o Textbook
o Outside source (NOT an encyclopedia) that you used in your introduction
Mitosis Lab
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Additional Questions:
a. Questions 1-4 and 7-12 must be typed in the pre-lab.
b. Questions 1-4 must be answered in the Pre-lab.
c. Questions 5-6 must be completed on this sheet when you submit the Pre-lab.
d. Question 6 – microscope drawing must be completed for the FINAL formal lab report.
e. Questions 7-12 must be completed for the FINAL formal lab report.
1. Describe what mitosis is.
2. State three situations that require cells to go through mitosis.
3. Purpose – State the purpose of this lab.
4. Claim – Think about how long it might take each cell to complete the process of dividing (mitosis) compared
to the time the cell is not dividing (interphase). Type the following statement/claim in your pre-lab and
complete each blank as to what you think. Include a rationale for why you think these percentages are
accurate.
Cells are in interphase about _______% of the time and are in mitosis about ___________% of the time.
(Note: Since the cell cycle is made of interphase and mitosis these two numbers must equal 100%.)
5. Fill in the outline for the stages of the cell cycle using the diagrams on p 281, 282, and 283. You can do this
right on this handout and NOT include it in your typed pre-lab.
a. ___________________________
i. ____________________
ii. ____________________
iii. ____________________
b. ___________________________
i. _____________________
1. ____________________
2. ____________________
3. ____________________
4. ____________________
ii. __________________________
Mitosis Lab
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6. Complete the tables on the following two pages EXCEPT for the drawing under the microscope. Note: You
will complete the microscope drawings during the lab and submit those drawings with your formal lab
report.
7. Describe two specific ways in which the actual onion cells in a particular stage look DIFFERENT from the ones
in the diagrams we have seen so far.
8. Describe two specific ways in which the actual onion cells in a particular stage look SIMILAR to the ones in the
diagrams we have seen so far.
9. You can determine the percentage of time a cell is in mitosis and interphase by looking at many cells and
calculating how many cells are in each phase. Use Figure 1, Onion Root Tip Cells to complete the blanks to
the right of Figure 1.
Figure 1 – Onion Root Tip Cells
Total # of cells _______
# in Interphase _______
# in Mitosis ______
% in Interphase ______
% in Mitosis _______
10. Was your claim (in Question #4) supported or negated/falsified by the data in Question #9? Use the data
from Question #9 to support your answer.
11. What about the tips of onion roots might make them a unique case with regards to the proportion of cells in
mitosis and interphase? In other words: what are root tips doing that might alter the proportion?
12. How might the percentage of cells in interphase vs. mitosis differ in an area that is not growing rapidly, such
as a fully-grown leaf of the onion plant? WHY?
Mitosis Lab
Metaphase
Prophase
Interphase
List the main events that
occur in the cell during this
stage
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Diagram of this stage based on
textbook
Drawing of this stage from
observations under microscope
Mitosis Lab
Cytokinesis
Telophase
Anaphase
List the main events that
occur in the cell during this
stage
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Diagram of this stage based on
textbook
Drawing of this stage from
observations under microscope
Mitosis Lab
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Final Formal Lab Requirements:
 Cover Page (Revised (if necessary) from Pre-lab)
 Introduction (Revised (if necessary) from Pre-lab)
o Explain how the topic is related to the real world. You might consider learning about different types
of cells and when and why they divide. Cite information from your textbook AND at least one
outside source (NOT an encyclopedia). You must use parenthetical references.
o Include definitions of relevant terms (in sentence form).
o Briefly state the purpose of the experiment.
o Write the claim and your rationale (from Question # 4 in the “Additional Questions” below) – but DO
NOT use first person.
 You will NOT have the following sections:
o Materials
o Procedures
o Results
 Additional Questions (Revised (if necessary) and completed from Pre-lab)
 Conclusion –In paragraph form, discuss the following:
o Interpretation of what you observed in the lab experiment as it relates to the purpose of the lab.
o Explain how the mitosis and/or the rate of mitosis of different cell types may relate to the real world.
Cite information using parenthetical references from at least one outside source. You may NOT use
the same source as in the Introduction. You many NOT use information from an encyclopedia.
 References – (Revised from Pre-lab) including:
o Textbook
o Outside sources (NOT an encyclopedia) that you used in your introduction and the new source for
your conclusion
Notes:
1. Your lab should never be written in first person. Examples of this include, but are not limited to: I, we and
my.
2. Lab report grading will reflect proper grammar, spelling, presentation, neatness, etc.