Ap Biology Unit 4 Lab Report

Lab 4 Thoughtful Observation

In this lab, we viewed Allium Root Tip and Whitefish Blastula cells under the microscope in order to view the different stages of Mitosis. The purpose of this activity was to visualize the process of cell reproduction, and the results of our experiment conclude that 44% of the Whitefish Blastula cells were in Prophase, 18% in Metaphase, 21% in Anaphase, and 17% in Telophase, so cells generally spend a longer amount of time in Prophase.

The results of the lab showed that cells spend more time in Prophase and Anaphase than Metaphase and Telophase because Prophase and Anaphase involve more movement of the chromosomes and mitotic spindles than Metaphase and Telophase where just one or two minute things occur. Although it is not a phase in mitosis, Interphase was seen in many of the cells, and if we had included Interphase in finding the percentages,

it would have definitely been the highest of the five for several reasons. First, Interphase takes up about 90% of the cell cycle and has four stages included: G1 where the cell grows and increases the cytoplasm, proteins, and organelles; S where cell growth and data replication occurs; G2 where cell growth continues, and some cells go through the G0 where the cell exits the cycle if it fails to pass through the various checkpoints.
In lecture, we are currently discussing the processes of cell reproduction.

Mitosis describes the reproduction of somatic cells, and Meiosis describes the reproduction of sex cells. We have discussed that Interphase, although not actually a part of Mitosis, is the longest phase and that Prophase involves the dissolution of the nuclear envelope, the condensing of chromatin into chromosomes, and the formation of mitotic spindles that attach to the centromeres of the chromosome pairs. After Prophase comes Metaphase where the chromosomes line up in the center of the cell at the metaphase plate. Next, Anaphase occurs where sister chromatids separate to become two separate chromosomes that then move to opposite poles of the cell. This results in the cell’s shape becoming elongated and the chromosome pairs splitting apart. Lastly, Telophase follows Anaphase and nuclei form around the two sets of chromosomes that then become less condensed. In Telophase, the microtubules break down too, and this phase is overlapped at the end of Mitosis with Cytokinesis that involves the final splitting of the two

cells.
The significance of this activity was to visualize the stages of mitosis in both plant and animal cells, and this can be applied to other forms of science like cancer research and environmental science. Cancer research requires knowledge of cell reproduction in order to find a way to successfully stop over-production of cells. Environmental scientists use knowledge of mitosis when finding ways to prevent particular plants from cell reproduction when harmful pesticides or chemicals are present. Potential problems we could have faced could have been recounting the same cells over again when we were pointing out twenty-five different cells in one of the four stages of mitosis. There is no specific way that we could have prevented this problem, but we tried to move from side to side to avoid this issue as much as possible. This activity was very helpful in allowing me to visualize the cell cycle from a personal point of view.