Mitosis Lab
1. Labeled Diagrams from Cells
Roots consist of different regions. At the tip of the root, you will find the root cap, which functions to protect the cells of the root as they descend into the soil. Just above the rood cap, you will find the region of cell division (apical meristem), which is the area where growth occurs. It is here that cells are actively dividing in order to lengthen the root.
- On a microscope under low power, locate the apical meristem region.
- Switch to medium power and high power. Locate a cell in Interphase. Draw the cell and label the Nucleus and Chromatin.
- Next, locate a cell in Prophase and draw it. Label the chromosomes. Can you see chromatids?
- Next, locate a cell in Metaphase and draw it. Label the kinetochore area and spindle fibers.
- Now, find a cell in Anaphase and draw it. What happens to the chromosomes at this stage?
- Find a cell in Telophase and draw it. Label the cleavage furrow, cell plate, and re-forming nuclei. What accompanies telophase in dividing cells?
1a. Data Tables
1a. Analysis Questions
Explain how mitosis leads to two daughter cells, each of which is diploid and genetically identical to the original cell?
At the beginning of mitosis during prophase, the chromosomes connect by a centromere and the nuclear envelop starts to disappear. In metaphase, the sister chromatids align at the center by microtubules which detach in anaphase and move to opposite poles of the cells. Telophase involves a nuclear envelope and cleavage furrow which is covered in the separated identical DNA. Finally the daughter cells form by cytokinesis and are genetically identical to the original cell due to the splitting of the DNA.
What is the cell doing at interphase?
In interphase, the cell grows in the G1 phase and absorbs necessary energy from nutrients to help with cell division. In the S phase, DNA is replicated and synthesized which allows for the reattachment of nucleotides to the double helix strands creating two new sister chromosomes. The final phase of interphase is G2 where the cell continues growth and preparation for cell division.
Contrast mitosis in plant and animal cells.
Mitosis in plant and animal cells differ in the building process of the spindle apparatus at the centrosome. Animal cells have two centrioles in the centrosome but most plants have a centrosome that lacks in centrioles. Also, animal cells form a cleavage furrow at the end of telophase and during cytokinesis. Plant cells have a cell plate instead of a cleavage furrow which forms in the “mother” cell.
Based on your data, what can you infer about the relative length of time an onion root tip spends in each stage of cell division?
The onion root tip spends the most time in interphase, then prophase, telophase, and the lease amount of time in metaphase and anaphase. The more cells seen in each phase, the longer the phase was.
(Pie chart shown above)
At the beginning of mitosis during prophase, the chromosomes connect by a centromere and the nuclear envelop starts to disappear. In metaphase, the sister chromatids align at the center by microtubules which detach in anaphase and move to opposite poles of the cells. Telophase involves a nuclear envelope and cleavage furrow which is covered in the separated identical DNA. Finally the daughter cells form by cytokinesis and are genetically identical to the original cell due to the splitting of the DNA.
What is the cell doing at interphase?
In interphase, the cell grows in the G1 phase and absorbs necessary energy from nutrients to help with cell division. In the S phase, DNA is replicated and synthesized which allows for the reattachment of nucleotides to the double helix strands creating two new sister chromosomes. The final phase of interphase is G2 where the cell continues growth and preparation for cell division.
Contrast mitosis in plant and animal cells.
Mitosis in plant and animal cells differ in the building process of the spindle apparatus at the centrosome. Animal cells have two centrioles in the centrosome but most plants have a centrosome that lacks in centrioles. Also, animal cells form a cleavage furrow at the end of telophase and during cytokinesis. Plant cells have a cell plate instead of a cleavage furrow which forms in the “mother” cell.
Based on your data, what can you infer about the relative length of time an onion root tip spends in each stage of cell division?
The onion root tip spends the most time in interphase, then prophase, telophase, and the lease amount of time in metaphase and anaphase. The more cells seen in each phase, the longer the phase was.
(Pie chart shown above)
1b. Hypothesis
Null Hypothesis: If treated with lectin, there will be no change in growth or reproduction within the cell cycles of the onion cells.
Alternate Hypothesis: There will be an increase in development within the onion cells after the lectin protein is added which will produce more cells overall, and the cells will spend less time in interphase and more time in mitosis because lectin tells the cells to divide
Alternate Hypothesis: There will be an increase in development within the onion cells after the lectin protein is added which will produce more cells overall, and the cells will spend less time in interphase and more time in mitosis because lectin tells the cells to divide