Experiment 1: Observation Of Mitosis In A Plant Cell Submit Assignment
Instructions: Read and perform the following experiment and download the forms supplied below.
Once you have completed the form, upload the completed form.
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PROCEDURE
PART 1: CALCULATING TIME SPENT IN EACH CELL CYCLE PHASE
The length of the cell cycle in the onion root tip is about 24 hours. Predict how many hours of the 24-hour cell cycle you think each step takes. Record your predictions, along with supporting evidence, in Table 1.
Click the microscope image in the materials section to examine the onion root tip slide images in the slide viewer. Eachimage displays a different field of view. Pick one of the images, and count the number of cells in each stage. Then, count thetotal number of cells in the image. Record the image you selected and your counts in Table 2.
Calculate the percentage of time spent by a cell in each stage based on the 24-hour cell cycle. Use the following equation below, and record the percentages in Table 2.
PART 2: IDENTIFYING STAGES OF THE CELL CYCLE
Observe the images of the onion root tip.
Locate a good example of a cell in each of the following stages: interphase, prophase, metaphase, anaphase, and telo-
phase.
Draw the dividing cell in the appropriate area for each stage of the cell cycle, exactly as it appears in the slide images. In-
clude your drawings in Table 3.
EXPERIMENT 1: OBSERVATION OF MITOSIS IN A PLANT CELL
Data Tables
Table 1: Mitosis Predictions
Predictions
Supporting Evidence
Table 2: Mitosis Data
Stage
Number of Cells in Stage
Total Number of Cells
Calculated % of Time Spent in Stage
Interphase
Prophase
Metaphase
Anaphase
Telophase
Cytokinesis
Table 3: Stage Drawings
Cell Stage
Drawing
Interphase
Prophase
Metaphase
Anaphase
Telophase
Cytokinesis
Post-Lab Questions
1. Label the arrows in the slide image with the appropriate stage of the cell cycle.
A ___________________
B ___________________
C ___________________
D ___________________
E ___________________
F ___________________
2. In what stage were most of the onion root tip cells? Does this make sense?
3. As a cell grows, what happens to its surface area-to-volume ratio (hint: think of a balloon being blown up)? How does this ratio change with respect to cell division?
4. What would happen if mitosis were uncontrolled?
5. How accurate were your time predictions for each stage of the cell cycle?
6. Discuss one observation you found interesting while looking at the onion root tip cells.
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