Lab 3 Mitosis and Meiosis

Lab 3 Mitosis and Meiosis BIO201L Straighterline Anatomy & Physiology I BIO 201L Lab 3 Mitosis and Meiosis Worksheet – with all lab photos (New Version June 2024) Scored 100% Student Name: Access Code (located on the lid of your lab kit): Lab Report Format Expectations Utilize college level grammar and professional formatting when completing this worksheet. Submissions without proper formatting, all required photos or sufficient responses will be rejected. Pre-lab Questions 1. What are chromosomes made of? Chromosomes are comprised of single molecules of DNA and protein. 2. Compare and contrast mitosis and meiosis, ensuring to detail the differences in both function and in process. (Hint: Your response should be 4-5 sentences long.) Mitosis comprises five phases. Somatic cells are the site of it. The number of chromosomes stays the same while it generates two diploid daughter cells. Meiosis entails nine phases. In every daughter cell, the number of chromosomes is half. Its function is sex reproduction, which takes place in the germ cell. Both begin with a single parent cell, generate additional cells, and follow substantially the same basic procedures. 3. Cancer is a disease related to uncontrolled cell division. Investigate two known causes for these rapidly dividing cells and use this knowledge to invent a drug that would inhibit the growth of cancer cells. (Hint: Your response should be 4-5 sentences long.) In cancer, cell division happens unrestricted and quickly on a constant basis. Mutations in the genes that regulate cell division brought on by exposure to mutagens in surroundings are one of the recognized significant causes of cancer. The second explanation is that the mutagenic genes are inherited from the parents. As of the present, cancer has no known cure. Tumor growth is managed by chemotherapy and radiation therapy. Since cancer affects various genes differently, it is unique. Drug development to limit cancer growth can be considered at multiple stops throughout the cell cycle. After determining the type of cancer and how to mitigate it, we may choose where to interrupt the cycle. Lab 3 Mitosis and Meiosis BIO201L EXPERIMENT 1: OBSERVATION OF MITOSIS IN A PLANT CELL Introduction Questions 1. State how you will calculate the number of hours each stage of mitosis takes based on observations. Do so by either stating the “Hours of Stage” equation, or by discussing the equation and its application. If you decide to insert an equation, you must use an equation editor to properly=24state× the equation with the e/correct symbols and fraction format. 2. In Table 1, below, predict how many hours of the 24-hour cell cycle you think each step takes. Ensure you provide robust supporting evidence to back your prediction. Table 1: Mitosis Predictions Predictions Supporting Evidence It will take roughly 20 hours for interphase, 3.5 hours for mitosis, and an hour or less for cytokinesis. The most extended period/most prolonged phase of the cell cycle is called interphase. Whereas cytokinesis is shorter than mitosis Lab 3 Mitosis and Meiosis BIO201L Data and Observations Record your observations in the table below. Based on those observations, calculate the percentage of time spent in each phase of mitosis. Table 2: Mitosis Data Chosen Image Onion root , 100X Stage Number of Cells in Stage Total Number of Cells Calculated % of Time Spent in Stage Interphase 17 30 56.68 Prophase 5 30 16.66 Metaphase 3 30 10.00 Anaphase 3 30 10.00 Telophase 2 30 16.66 Cytokinesis 0 30 0.00 Lab 3 Mitosis and Meiosis BIO201L Below, insert the drawings you generated of each phase of mitosis. You must include your handwritten name in the background. Submissions that do not meet this requirement will be rejected. Table 3: Stage Drawings Cell Stage Drawing Cell Stage Interphase Anaphase Prophase Telophase Drawing Lab 3 Mitosis and Meiosis Cell Stage Drawing Cell Stage BIO201L Drawing Cytokinesis Metaphase Results and Discussion 1. Label the arrows in the slide image below with the appropriate stage of the cell cycle. A. B. C. D. E. Interphase Cytokinesis Prophase Interphase Prophase F. Metaphase Lab 3 Mitosis and Meiosis BIO201L Lab 3 Mitosis and Meiosis BIO201L 2. What stage were most of the onion root tip cells in? Based on this observation, explain why this is to be expected. Since interphase is the most extended phase, the majority of the cells were identified at this stage. 3. As a cell grows, what happens to its surface area : volume ratio? (Think of a balloon being blown up). How is this changing ratio related to cell division? As a cell expands, its surface area to volume ratio falls. When the volume exceeds the surface area of the cell, the cells divide, which causes the ratio to change. 4. What is the function of mitosis in a cell that is about to divide? The purpose is to generate two diploid cells. 5. What would happen if mitosis were uncontrolled? The cell would divide quickly, resulting in cancer. 6. How accurate were your time predictions for each stage of the cell cycle? I was right on my predictions for every step. 7. Discuss one observation that you found interesting while looking at the onion root tip cells. The ability to observe the telophase creation of a new cell wall adjacent to a pre-divided cell was intriguing to me. Lab 3 Mitosis and Meiosis BIO201L EXPERIMENT 2: TRACKING CHROMOSOMES THROUGH MITOSIS Introduction Questions 1. Cite an example of a type of cell that undergoes mitosis. Why is it important for each daughter cell to contain information identical to the parent cell? Skin cells: All cells, such as skin cells that do not divide into gametes, go through mitosis. To ensure that there are no mutations, every daughter cell must get the same genetic information from the parent cell. 2. Hypothesize what would happen if the sister chromatids did not split equally during anaphase of mitosis. The sister chromatids could not have acquired the same genetic information as their parents. Genetic illnesses or mutations would exist. 3. Human skin cells divide at a higher rate than neurons (nerve cells). Hypothesize why this may be. Because the skin is an external organ, I hypothesize that skin cells multiply more quickly than nerve cells. Lab 3 Mitosis and Meiosis BIO201L Data and Observations Once you have completed the digital exercise, select the “Results Table” button at the bottom right-hand corner of the screen and select the “Generate PDF” button at the top of the following screen. Insert your download into this document by selecting the Insert > Object > Text from file. Resize if necessary. Lab 3 Mitosis and Meiosis Results and Discussion 1. How many chromosomes were present before mitosis? Every cell had 46 chromosomes. 2. How many chromosomes did each of the daughter cells contain after mitosis? 46 chromosomes. BIO201L Lab 3 Mitosis and Meiosis BIO201L EXPERIMENT 3: FOLLOWING CHROMOSOMAL DNA MOVEMENT THROUGH MEIOSIS Introduction Questions 1. List two differences between meiosis I and meiosis II. Sister chromatids split during meiosis II, whereas homologous chromosomes divide during meiosis I. Since meiosis I yields two diploid daughter cells, meiosis II yields only four haploid daughter cells. Meiosis I is the only time when genetic recombination, or crossing over, happens. 2. Why is it necessary to reduce the number of chromosomes in gametes, but not in other cells? Additional chromosomes can cause gene mutations that are typically lethal to children. Checkpoints reduce anomalies by detecting and correcting them. 3. What is the ploidy of the daughter cells at the end of meiosis I? What about at the end of meiosis II? Meiosis I has two haploid copies, but Meiosis II has four haploid cells. Lab 3 Mitosis and Meiosis BIO201L Data and Observations Once you have completed Part 1 of the digital exercise, take screenshots and insert them below. Resize if necessary. Table 5a (Meiosis I): Lab 3 Mitosis and Meiosis Table 5b (Meiosis II): BIO201L Lab 3 Mitosis and Meiosis BIO201L Once you have completed parts 2, 3, and 4, select the “View Data Table” button at the bottom left-hand corner of the home screen. Review your table. If you would like to make any changes, select the “Return” button in the bottom right-hand corner. If you are satisfied with your answers, take a screenshot and insert it below. Resize if necessary: Lab 3 Mitosis and Meiosis BIO201L Results and Discussion 1. How did crossing over affect the genetic content in the gametes? Use your results to support your answer. Crossing over produced non-identical gametes, altering the genetic composition. 2. Based on your observations in the digital exercise, what can you conclude about the severity of nondisjunction that occurs in meiosis I as opposed to meiosis II? Due to the degree of nondisjunction during meiosis I, two gametes were found to have an additional chromosome. Only one gamete possessed an additional chromosome during meiosis II. Meiosis I abnormalities would probably be more severe because half of the gametes had an extra chromosome. 3. Blue whales have 44 chromosomes in every cell. Determine how many chromosomes you would expect to find in the following: a. Sperm Cell: 22 chromosomes b. Egg Cell: 22 chromosomes c. Daughter Cell from Mitosis: 44 chromosomes d. Daughter Cell from Meiosis II: 22 chromosomes Lab 3 Mitosis and Meiosis BIO201L EXPERIMENT 4: THE IMPORTANCE OF CELL CYCLE CONTROL Introduction Questions 1. In this experiment, you will review some of the karyotypic differences that can be observed when comparing normal, controlled cell growth and abnormal, uncontrolled cell growth. What is a karyotype? Give the definition below. A image of every diploid chromosome in the body is called a karyotype. 2. Why do cells which lack cell cycle control exhibit karyotypes which look physically different from cells with normal cell cycle. The defects that result from unchecked cell development are reflected in karyotypes. 3. Record your hypothesis from Step 1 in the Procedure section here. An abnormal karyotype could be seen when comparing a cancerous cell's growth to that of a normal cell cycle. 4. What are HeLa cells? Why are HeLa cells appropriate for this experiment? Hela cell is a particular kind of immortalized human cell discovered from cervical cancer cells. HeLa cells are immortal due to their inability to expire. Lab 3 Mitosis and Meiosis BIO201L Data and Observations 1. Below, write a paragraph or paragraphs that detail(s) the observations you made during your research. To earn credit, describe the images you viewed, where you obtained them, and the differences you noted between the normal and abnormal karyotypes. (Hint: Your response must be thorough and will likely contain around 6-10 sentences.) You may include copies of the photos you reviewed, but these are not required for credit and will not be graded. In my research, I looked at numerous photos of both standard and aberrant karyotypes from credible academic papers and scientific sources while conducting my research. The chromosomes in a cell are represented graphically by a karyotype, which is usually arranged in pairs from largest to smallest. A typical human karyotype consists of 46 pairs of chromosomes. These consist of a single set of sex chromosomes, designated XY for men and XX for females, and twenty-two pairs of autosomes. On the other hand, aberrant karyotypes showed differences in chromosomal number or structure. For example, I saw images of people with Down syndrome, a disorder brought on by an extra copy of chromosome 21 (also known as trisomy 21). Rather than the typical pair, chromosome 21 was made up of three. Stuvia.com - The Marketplace to Buy and Sell your Study Material Lab 3 Mitosis and Meiosis BIO201L Results and Discussion 1. What do your results indicate about cell cycle control? The outcome suggests that a cancerous cell has minimal self-control. 2. Research the function of the protein called p53. What does this function do? Explain how it can affect cell cycle control. P53 is a tumor suppressor that coordinates cellular responses to stress and damage to their DNA It protects the integrity of the genome and lowers the chance of developing cancer because of its capacity to control the cell cycle, encourage DNA repair, and trigger apoptosis. Many cancer types frequently exhibit p53 dysfunction or loss of function, which permits aberrant cells to avoid apoptosis and growth arrest. This results in unchecked cell division and tumour formation. 3. What is the Philadelphia chromosome? How is this chromosome related to cancer? Identify how this chromosome appears physically different on a karyotype than it appears on a karyotype of normal chromosomes. The Philadelphia chromosome is an anomaly caused by a transference/ translocation event where a section of chromosome 9 and a segment of chromosome 22 swap locations. This hybrid gene produces an abnormal protein fusion with continuous tyrosine kinase activity. One of the main characteristics of cancer is unchecked cell growth and division, which is caused by this activity. Chromosome 22 seems to have a shorter karyotype than a typical chromosome. 4. Suppose a person developed a mutation in a somatic cell which diminishes the performance of the body’s natural cell cycle control proteins. This mutation resulted in cancer, but was effectively treated with a cocktail of cancer-fighting techniques. Is it possible for this person’s future children to inherit this cancer-causing mutation? Be specific when you explain why or why not. No, it is not possible since the cell is somatic, and those types of cells do not form gametes.The mutation that caused cancer happened in a somatic cell, a type of body cell different from the germ cells (eggs or sperm) that are in charge of transferring genetic information to offspring. The somatic mutations don't change the genetic makeup of the germ cells; the offspring do not inherit them. 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