Experiment 1: Following Chromosomal DNA Movement through Meiosis Experiment 1: Following Chromosomal DNA Movement through Meiosis

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Mitosis and Meiosis

Experiment 1: Observation of Mitosis in a Plant Cell In this experiment, we will look at the different stage of mitosis in an onion cell. Remember that mitosis only occupies one to two hours while interphase can take anywhere from 18 - 24 hours. Using this information and your experiment data, you can estimate the percentage of cells in each stage of the cell cycle.

Procedure

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 each step takes. Record your predictions, along with supporting evidence, in Table 1.

2. Examine the onion root tip slide images on the following pages. There are four images, each displaying 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 counts in Table 2.

3. Calculate the time spent by a cell in each stage based on the 24 hour cycle:

4. Locate the region just above the root cap tip.

5. Locate a good example of a cell in interphase, prophase, metaphase, anaphase, and telophase.

6. Draw the dividing cell in the appropriate area for each stage of the cell cycle. Include your drawings in Table 3.

Hours of Stage = 24 x Number of Cells in Stage

Total Number of Cells Counted

Materials

Onion (allium) Root Tip Digital Slide Images

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Mitosis and Meiosis

Onion Root Tip: 1000X

Chromosomes

Nucleus

Cell Wall

Cytoplasm

Chromosomes

Cell Wall

Cytoplasm

Nuclei

Onion Root Tip: 400X

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Mitosis and Meiosis

Onion Root Tip: 1000X

Onion Root Tip: 1000X

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Mitosis and Meiosis

Predictions:

Supporting Evidence:

Table 1: Mitosis Predictions

Number of Cells in Each Stage Total Number of Cells

Interphase:

Prophase:

Metaphase:

Anaphase:

Telophase:

Cytokinesis:

Calculated % of Time Spent in Each Stage

Interphase:

Prophase:

Metaphase:

Anaphase:

Telophase:

Cytokinesis:

Table 2: Mitosis Data

Cell Stage: Drawing:

Interphase:

Prophase:

Metaphase:

Anaphase:

Telophase:

Cytokinesis:

Table 3: Stage Drawings