Week 4 Midweek Assignment: Mitosis And Time Spent

Week 4 Midweek Assignment Mitosis determining The Time Spent In Each P

Week 4 Midweek Assignment: Mitosis Determining the Time Spent in Each Phase Using Whitefish Blastula A prepared microscope slide of whitefish blastula cross-sections will show cells arrested in various stages of the cell cycle. (Note: It is not visually possible to separate the stages of interphase from each other, but the mitotic stages are readily identifiable.) If 100 cells are examined, the number of cells in each identifiable cell-cycle stage will give an estimate of the time it takes for the cell to complete that stage. Given the events included in all of interphase and those that take place in each stage of mitosis, estimate the length of each stage based on a 24-hour cell cycle. Background Before you start this lab, you should read your materials in this section on the various phases. Additionally, the following YouTube video might be helpful as you watch an instructor identify cells in the various phases as he looks through a microscope. mitosis - whitefish Blastula (05:56) Finally, review a close-up view of cells at various stages Procedure Examine the first image below, and then read the counting methodology. Slowly scan the image below left to right, and up and down to view all the cells in the section. As you scan, you will notice that most of the cells are not undergoing mitosis but are in the interphase period of the cell cycle. Practice identifying the cells in the image below before beginning the actual experiment. The images below are of whitefish blastula in various stages mitosis. Before you count cells in the various phases, circle one example cell for each of the phases below and write the number next to the circle. You can draw the circle by selecting Draw in the Microsoft Word at the top and then selecting a pen. Drawing Table 1. Prophase 2. Metaphase 3. Anaphase 4. Telophase 5. Cytokinesis After you feel comfortable with your counting method and identifying cells in the various stages of mitosis, use the four images below of whitefish blastula to count the cells in each stage until you reach 100 total cells, recording your data below in Data Table 1. (You may not need to use all four images. Stop counting when you reach 100 total cells.) After totaling the cells in each stage, calculate the percent of cells in each stage. (Divide total of stage by overall total of 100 and then multiply by 100 to obtain percentage.) Data Table 1 Stage Totals Percent Interphase Mitosis: Prophase Metaphase Anaphase Telophase Cytokinesis Totals % To find the length of time whitefish blastula cells spend in each stage, multiply the percent (recorded as a decimal, in other words take the percent number and divide by 100) by 24 hours. (Example: If percent is 20%, then Time in Hours = .2 * 24 = 4.8) Record your data in Data Table 2. Data Table 2 Stage Percent Time in Hours Interphase Prophase Metaphase Anaphase Telophase Cytokinesis Conclusions 1. Drawing Table: Make sure you did the circle identifications with a number as mentioned with regards to the Drawing Table. 2. In your own words, explain the purpose of interphase. 3. In your own words, explain the purpose of mitosis. 4. Summary: Using complete sentences, write a summary of the results of the experiment. Be sure to talk about which ones seemed to be the faster and why that might be, and which are slower. 6 image1.png image2.png image3.jpeg image4.jpeg image5.jpeg image6.jpeg

Paper For Above instruction

The analysis of mitosis stages in whitefish blastula provides valuable insight into the temporal dynamics of cell division in a rapidly proliferating tissue. By examining 100 cells across various microscopic images, the proportion of cells in each stage of mitosis can be determined, which allows for estimating the duration of each phase within a standardized 24-hour cell cycle. This study is instrumental in understanding cellular behavior during development and tissue growth and has broader implications for cell biology and related biomedical research.

The primary purpose of interphase is to prepare the cell for division by allowing it to grow, produce necessary proteins, and replicate its DNA. Interphase comprises the G1, S, and G2 phases, during which the cell carries out normal functions while preparing for mitosis. The importance of this phase lies in ensuring the cell's genome is accurately replicated and that cellular components are sufficient to support two daughter cells. Any errors in this phase can lead to genetic abnormalities, underscoring its critical role in maintaining genetic stability.

Mitosis, on the other hand, is the process by which a single parent cell divides to produce two genetically identical daughter cells. Its purpose is to facilitate growth, tissue repair, and asexual reproduction in multicellular organisms. Mitosis ensures that each daughter cell receives an exact copy of the parent cell’s genome, preserving genetic continuity across cell generations. This process involves a series of highly coordinated steps—prophase, metaphase, anaphase, telophase, and cytokinesis—that meticulously segregate and distribute duplicated chromosomes, thereby maintaining genetic fidelity.

Based on the observations from the microscopy images, it is evident that the majority of cells are in interphase, constituting a significant portion of the cell cycle. This aligns with biological expectations, as interphase is typically the longest stage, often accounting for approximately 90% or more of the total cycle duration in rapidly dividing cells. In the images analyzed, mitotic stages such as prophase, metaphase, anaphase, and telophase represented a smaller percentage of cells, reflecting their shorter durations.

The data revealed that the metaphase stage had a higher percentage of cells compared to other mitotic phases, indicating it may last longer or be more easily identifiable within the sample. Conversely, anaphase appeared to have the shortest percentage of cells in that stage, suggesting it is a brief but critical phase in chromosome segregation. By converting these percentages into time estimates, it was determined that interphase occupies approximately 20 hours of the 24-hour cycle, reaffirming its role as a preparatory phase. Prophase and metaphase durations were found to be shorter, while cytokinesis and telophase showed intermediate times, consistent with their biological functions.

Overall, these findings underscore the rapid progression through certain mitotic phases, especially anaphase, which involves swift chromosome separation, and the prolonged nature of interphase to ensure correct DNA replication and cell growth. Understanding these dynamics is crucial for insights into developmental biology, cancer research, and tissue regeneration, where dysregulation of cell cycle phases often occurs. Future studies could focus on molecular regulators specific to each phase to further elucidate the mechanisms controlling cell division timing.

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