Observing Mitosis Lab
Question
• How do actual cells going through mitosis differ from the diagrams
and drawings that we are familiar with?
Background Information
• What is a distinguishing characteristic?
• List the distinguishing characteristic of each phase of Mitosis.
Background Information
• We will be viewing prepared slides of onion root tip, Fish blastulas,
and Ascaris. All three of these are readily available and are from
regions of an organism where cells are rapidly dividing, so you should
expect to see many cells in various stages of the cell cycle.
• You may not have the same type of slide as the people on either side
of you, so do not worry if your drawings don’t look anything like
theirs.
• Part of your grade for this lab will be based on your ability to locate
cells in each phase of cell division. I will be walking around the room.
When you find a cell that you can identify, raise your hand. I will
come look at it, and sign off on each. You should work on sketching
your diagram while waiting for me.
• You will be viewing actual cells, which have a full set of chromosomes,
rather than an educational diagram. The cells on the slide will not
look exactly like you might be expecting, so look for general
characteristics. Your drawings should reflect what you are seeing.
Prediction
• Write how you expect the actual cells to look different from the
diagrams that you have been shown of each phase of Mitosis.
Instructions:
1. Record the type of slide you will be viewing.
2. Place it onto the microscope. Focus on high power, using course
adjustment.
3. Switch to medium power. Focus using fine adjustment ONLY.
Adjust slide as needed to locate cells going through division.
4. Switch to high power. Focus using fine adjustment ONLY. When you
have identified one of the phases of mitosis, begin sketching. Raise
your hand to have me come look at your slide and sign off.
5. Repeat steps 3-4 for the remaining phases of mitosis.
Observations – onion root tip
Observations – whitefish blastula
Conclusion questions
1. The roots of an onion are actively growing. How might the numbers of
dividing cells found in this region differ from a different part of the plant?
2. A blastula is an early multicellular embryo stage following fertilization.
Why does this make them a good choice for observation during this lab?
3. What process must take place before mitosis can begin?
4. Why is mitosis important (list two purposed mitosis serves in the body)?
Where does mitosis take place?
5. What type of cells in your body do not divide by mitosis? How do they
divide?
6. There are cells in your body that do not divide. Give one example.