Mitosis Onion Root Tip Lab

1. What patterns exist in your data?  In which stage of the cell cycle are most of the cells you examined?  How does this data support what you know about the cell cycle?

There are no particular number patterns that exist in my data. However, with both samples, the amount of cells in the interphase phase of the cell cycle was increasingly higher than the amount of cells in the other four stages. Based on my data, most of the cells that were examined were in the interphase phase. This data supports my previous knowledge of the cell cycle as cells are known to spend most of their life cycle in the interphase stage. This stage is known for the growth and development of the cell and for the replication of DNA and organelles and for aiding in the production of new cells. This stage is also the longest stage as the development of the cell occurs here, proving why my data showed an increasingly large amount of cells in the interphase stage whereas the other stages of the cell cycle showed lower amounts.

 

2. Find the average percentage of cells in each stage of the cell cycle among the three samples.  Assume that a cell takes 24 hours to complete one cell cycle.  Calculate how much time is spent in each stage of the cell cycle.  (Hint: Multiply the percentage of cells in each stage, as a decimal, by 24 hours).

The amount of time spent in the interphase stage of the cell cycle is about 14.5 hours, in the prophase stage the cell spends about 2.7 hours, in the metaphase stage the cell spends about 2.3 hours, in the anaphase stage the cell spends about 1.9 hours, and in the telophase stage the cell spends about 1.7 hours.

 

3. The cells in the root of an onion are actively dividing.  How might the numbers you count here be different than if you had examined cells from a different part of the plant?

The number of cells that are examined in the root of an onion are actively dividing, meaning that the amount of cells counted increases in number as there are many cells in the interphase phase of the cell cycle. In contrast, the amount of cells examined in a different part of the plant will be less in number as more cells have reached a mature age and are in their telophase phase of life. This would also make it easier to observe cells as they are not dividing as rapidly. A mistake that could have occurred during my experiment was observing the most populated area on my onion root tip as cells were dividing rapidly. In the future, it is vital to observe sections of the onion root tip where more cells are present in the telophase stage for easier examination.

 

4. Using the data from Table 2, create a graph in Google Spreadsheets using the % of cells in each stage of Mitosis.  Add a title and label the graph.  Upload a picture of the graph to your post.

 

Stages of Cell Cycle vs. Average Number of Cells

Phase	Average % Number of Cells
Interphase	63.05%
Prophase	11.36%
Metaphase	9.90%
Anaphase	8.01%
Telophase	7.21%

5. A chemical company is testing a new product that it believes will increase the growth rate of food plants.  Suppose you are able to view the slides of a plant’s root tips that have been treated with the product.  If the product is successful, how might the slides look different from the slides you viewed in this lab?

If the product is successful, The slides that are treated with the new chemical product will look different when viewed under a microscope in comparison to the slides that I viewed in this lab as the rate of cell division and life in each stage of mitosis will be faster. More cells will be going through the interphase stage of their life faster and more cells will be ready to go through the mitosis stage in order to divide. This application of the new chemical onto the plant’s root tips in order to view cells go though the stages of mitosis at a quicker rate is similar to how scientists stain specimens before viewing under a microscope. Earlier in the year, through different experiments involving viewing onion, cheek and elodea cells under a microscope, the class determined that staining the specimens allows for cells to be exposed and easier viewed. This is similar to the new chemical product as they are both used to view specimens more easily but for different purposes.

 

6. Design an experiment that would test the product described in question 5.  Explain what you could test or do to show that the product really does increase the rate of cell growth and division in plants.  Assume the product is a liquid that can be added to the soil in which the plant is growing.

Experiment:

Question: Will a plant who soil is treated with a product that claims to increase the growth rate of food plants grow more then a plant whose soil is treated only with water when treated each for five days?

Hypothesis: If a plant whose soil is treated with a product that claims to increase the growth rate of food plants for five days, then the plant will grow more than a plant whose soil is only treated with water because the plant will be absorbing more nutrients than the other plant who is only receiving water and no fertilizer.

Prediction: The plant whose soil is treated with a product that claims to increase the growth rate of food plants will grow more than the plant whose soil is only treated with water.

Variables:

Independent Variables: The independent variables are the application of water and the chemical product to the plants.

Dependent Variable: The dependent variable is the amount of plant growth for each plant.

Control: The control is the plant whose soil is only treated with water.

Constants: The constants are the place where the plants are kept, the five day time period and the amount of water and chemical product given each day.

Procedure:

1. First, fill two small pots with soil leaving a few centimeters at the top clear, making sure to use a small shovel to do so.

2. Second, obtain two identical plant seeds and place one into each of the two small pots, burying the seed near the surface and patting soil on top.

3. Fill two cups of water and pour into one of the small pots. Repeat with the next pot.

4. Next, fill one cup with the chemical product and pour into one of the pots. The pot that hasn’t been treated with the product is the control.

5. Place both pots in a designated area with sunlight available.

6. Wait for five days before retrieving the two pots.

7. After five days, retrieve the two pots and make qualitative and quantitative observations about which plant grew more in the given time period.

2 thoughts on “Mitosis Onion Root Tip Lab

  1. DC: there is a pattern in your data and you actually found it, more cells are in interphase; cell graph type isn’t correct, we are comparing proportions or ratios so it should be a pie graph; 1

    AS: 5

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