cycle and many of the cells you will be looking at are in interphase. ... takes the same amount of time, how many hours old is a cell that is just sta...
Lab. Experiment Cell Division and Mitosis Purpose: To examine onion and ascaris cells under a microscope and identify the different stages of cell division and identify the different phases of mitosis. Pre-Lab: Mitosis can be observed in cells that are in a state of growth. In this lab, you will observe cells and identify which stage of cell division the cells are in. To help you do this, let's review what characteristics to look for at the different stages. Also remember, interphase is not technically a part of Mitosis, but it is part of the cell cycle and many of the cells you will be looking at are in interphase. Based on your knowledge and reading, identify each stage of cell division (include the phases of mitosis) on the chart below and describe what you would expect to see. Stage
Distinguishing Characteristics
Hypothesis/Predictions: I think that the __________________________ will be the easiest stage to identify because________________ __________________________________________________________________________________________ I predict that most cells will be in (name the stage/phase of mitosis) __________________________________ because___________________________________________________________________________________
Materials: Microscope Onion Root Tip Slide Ascaris Slide Color Pencils
Procedure: 1. Carefully read the Background Information: Introduction, Interphase, Prophase, Metaphase, Anaphase, Telophase and Cytokinesis.
Scan the QR Code for background info
2. You will look at a slide of an onion root and ascaris through the microscope. Look for several cells in the process of cell division and search for organized blocks of cells where nuclei are plainly visible. (Most activity will be occurring at the tip of the root). Move the slide around until you find a good spot that shows the cells in various stages of mitosis. 3. Observe the specimen with the microscope. Use the low objective first. Sketch what you see in detail using purple color pencil. Switch to the medium power and sketch what you see in detail using purple color pencil, and eventually to the high power. Please be careful! Then complete the chart. Phases of Mitosis The following diagram shows onion cells undergoing mitosis or in the stage of Interphase. Each cell is numbered. For each cell, identify the phase of mitosis or if it’s in Interphase, and provide evidence for your answer.
1. _____________________
10. _____________________
2. _____________________
11. _____________________
3. _____________________
12. _____________________
4. _____________________
13. _____________________
5. _____________________
14. _____________________
6. _____________________
15. _____________________
7. _____________________
16. _____________________
8. _____________________
17. _____________________
9._____________________
18. _____________________
Data/Observations: ASCARIS CELLS:
*Low Power 40x
*Medium Power 100x
*High Power 400x
*(Complete this chart using the low, medium, and high power objectives) Stage
Interphase (outline in red)
Prophase (outline in orange)
Metaphase (outline in green)
Anaphase (outline in yellow)
Telophase (outline in blue)
Sketch
Estimated Number of Cells (low power objective)
ONION ROOT TIP CELLS:
Low Power 40x
*Medium Power 100x
*High Power 400x
*(Complete this chart using the medium and high power objectives) Stage
Interphase (outline in red)
Prophase (outline in orange)
Metaphase (outline in green)
Anaphase (outline in yellow)
Telophase (outline in blue)
Sketch
Estimated Number of Cells (medium power objective)
Discussion/Conclusion/Analysis: 1. Why is the onion root a good specimen for studying mitosis?
2. The majority of the cells in the onion root were in which stage of the cell cycle?
3. The majority of the cells in the asceris were in which stage of the cell cycle?
4. In allium, interphase lasts about 15 hours, and mitosis takes up 80 minutes. Assuming that each stage of mitosis takes the same amount of time, how many hours old is a cell that is just starting anaphase. (Yes, you'll need to do some math here - show your work or explain your reasoning)
5. Sketch one cell in any stage of mitosis. Label the stage and label any cell structures that are visible. The spindle fibers and chromosomes should be visible.
6. Which stage of mitosis is the easiest (in your opinion) to see on the slide? What about it makes it easy to identify?
Math Problems 7. What percentage of the onion root cells are in interphase? 8. What percentage of the onion root cells are in metaphase 9. What percentage of the asceris cells are in interphase? 10. What percentage of the asceris cells are in metaphase?
