Introduction to Science Observation of Mitosis in a Plant Cell

Experiment Inventory

Materials Onion Root (Allium) Mitosis Slide Viewer

EXPERIMENT 1: OBSERVATION OF MITOSIS IN A PLANT CELL

In this experiment, you will observe the different stages of mitosis in an onion cell. Keep in mind that mitosis occupies only one to two hours of the cell cycle, while interphase can last anywhere from 18 – 24 hours. Using this information and the data from your experiment, you can estimate the percentage of cells in each stage of the cell cycle.

PROCEDURE

PART 1: CALCULATING TIME SPENT IN EACH CELL CYCLE PHASE

1. 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.

2. Click the microscope image in the materials section to examine the onion root tip slide images in the slide viewer. Each

image displays a different field of view. Pick one of the images, and count the number of cells in each stage. Then, count the

total number of cells in the image. Record the image you selected and your counts in Table 2.

3. 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.

Experiment 1

PART 2: IDENTIFYING STAGES OF THE CELL CYCLE

1. Observe the images of the onion root tip.

2. Locate a good example of a cell in each of the following stages: interphase, prophase, metaphase, anaphase, and telo-

phase.

3. 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.

© eScience Labs, 2016

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Data SheetExperiment 1 Data Sheet Table 1: Cell Cycle 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

© eScience Labs, 2016