Lab 3 Mitosis and Meiosis PDF

Preview

Summary

Straighterline A&P 1 Lab 3 worksheet Mitosis and Meiosis....

Description

Lab 3 Mitosis and Meiosis

BIO201L

Student Name: Robert Prieskorn Access Code (located on the lid of your lab kit): AC-QHNVPF8

Pre-Lab Questions ”1. What are chromosomes made of?” Chromosomes are made up of a DNA-proteins called chromatin that is organized into subunits called nucleosomes.

”2. Compare and contrast mitosis and meiosis. ” Compare: Both are involved in making new cells. Both start with 2 sets of chromosomes. Contrast: Meiosis creates gametes while Mitosis makes body cells. Mitosis occurs in somatic cells (no synapsis or crossing over) and Meiosis happens in germ cells (synapsis and crossing over take place).

”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. ” There are two types of cancer, environmental and genetic. The drug that I would invent would target the receptors of the cancer cell and destroy the replication process.

Experiment 1: Observation of Mitosis in a Plant Cell Table 1: Mitosis Predictions

Predictions

I predict that interphase will take approximately 20 hours, mitosis phase will take 3 hours and cytokinesis will take 30 minutes.

Supporting Evidence

Interphase will be the longest phase. The cycle completes in approximately 18-24 hours.

Table 2: Mitosis Data Onion Root Tip, 100x. Image 4/4

Chosen Image Stage

Number of Cells in Stage

Total Number of Cells

Calculated % of Time Spent in Stage

Interphase

20

25

80%

Prophase

2

25

8%

Metaphase

0

25

0%

Anaphase

1

25

4%

Lab 3 Mitosis and Meiosis Chosen Image

BIO201L

Onion Root Tip, 100x. Image 4/4

Stage

Number of Cells in Stage

Total Number of Cells

Calculated % of Time Spent in Stage

Telophase

1

25

4%

Cytokinesis

1

25

4%

Lab 3 Mitosis and Meiosis

BIO201L

Table 3: Stage Drawings

Cell Stage

Interphase

Drawing REMEMBER: Your drawings should have your name and access code handwritten in the background.

Lab 3 Mitosis and Meiosis Cell Stage

Prophase

BIO201L

Drawing REMEMBER: Your drawings should have your name and access code handwritten in the background.

Lab 3 Mitosis and Meiosis Cell Stage

Metaphase

BIO201L

Drawing REMEMBER: Your drawings should have your name and access code handwritten in the background.

Lab 3 Mitosis and Meiosis Cell Stage

Anaphase

BIO201L

Drawing REMEMBER: Your drawings should have your name and access code handwritten in the background.

Lab 3 Mitosis and Meiosis Cell Stage

Telophase

BIO201L

Drawing REMEMBER: Your drawings should have your name and access code handwritten in the background.

Lab 3 Mitosis and Meiosis Cell Stage

BIO201L

Drawing REMEMBER: Your drawings should have your name and access code handwritten in the background.

Cytokinesis

Post-Lab Questions ”1. Label the arrows in the slide image below with the appropriate stage of the cell cycle. ” A- Interphase B- Cytokinesis C- Prophase D- Interphase E- Prophase F- Anaphase

Lab 3 Mitosis and Meiosis

BIO201L

Lab 3 Mitosis and Meiosis

BIO201L

”2. What stage were most of the onion root tip cells in? Why does this make sense? ” Most of the onion root tips cells were undergoing interphase. Since interphase takes so long, 18-24 hours, is why most of the onion tip roots were in 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? ” When the cell grows the surface area to volume ratio decreases. The cell is like the balloon in the fact that when the balloon can no longer handle the larger volume it pops the same principle applies with the cell when there is no more volume cell division, “pop”, happens. ”4. What is the function of mitosis in a cell that is about to divide? ” To ensure that the sister chromatids segregate into two daughter cells. ”5. What would happen if mitosis were uncontrolled? ” It would replicate the cells rapidly and repeatedly. Uncontrolled mitosis can lead to cancer. ”6. How accurate were your time predictions for each stage of the cell cycle? ” My predictions were skewed. My prediction for interphase was closest to correct, after reviewing the onion root slides it was observed that most of the cells were in interphase. ”7. Discuss one observation that you found interesting while looking at the onion root tip cells.” One observation that I found interesting was cytokinesis on slide 4/4. To see the cell division was interesting.

Experiment 2: Tracking Chromosomes Through Mitosis 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

BIO201L

Post-Lab Questions 1. How many chromosomes were present before mitosis?

46 chromosomes were present before mitosis. 2. How many chromosomes did each of the daughter cells contain after mitosis?

2 daughter cells both containing 46 chromosomes. 3. 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?

Somatic cells, specifically blood cells. It is important for each daughter cell to contain information identical to the parent cell because those cells will have the same job. 4. Human skin cells divide at a higher rate than neurons (nerve cells). Hypothesize why this may be.

Hypothesis: Skin cells are easily sloughed, so they need to reproduce faster. 5. Hypothesize what would happen if the sister chromatids did not split equally during anaphase of mitosis. If the sister chromatids did not split equally during anaphase the end result would be down syndrome.

Experiment 3: Following Chromosomal DNA Movement through Meiosis Part 1: Once you have completed the digital exercises, take screenshots and insert them below. Resize if necessary. Table 5a (Meiosis I):

Lab 3 Mitosis and Meiosis

BIO201L

Table 5b (Meiosis II):

Parts 2, 3, and 4: Once you have completed the digital exercise, select the “View Data Table” button at the bottom left-hand corner of the home screen. Review your table. If you would

Lab 3 Mitosis and Meiosis

BIO201L

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:

Post-Lab Questions 1. How did crossing over affect the genetic content in the gametes? Use your results to support your answer.

Crossing over affected the genetic content in the gametes by creating genetic diversity because the chromatids held together by the centromere were no longer identical. 2. What is the ploidy of the daughter cells at the end of meiosis I? What about at the end of meiosis II?

End of Meiosis I is two diploid daughter cells. End of meiosis II are are four haploid daughter cells. 3. List two differences between meiosis I and meiosis II.

Meiosis I produces 2 diploid daughter cells; meiosis II produces for 4 haploid daughter cells. Crossing over only occurs in Meiosis I. 4. 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?

Down Syndrome or Turner’s syndrome can occur if nondisjunction occurs. The difference between the two is that nondisjunction in meiosis 1 occurs in the

Lab 3 Mitosis and Meiosis

BIO201L

homologous chromosomes while nondisjunction in meiosis 2 occurs in sister chromatids. 5. Why is it necessary to reduce the number of chromosomes in gametes, but not in other cells? If the numbers were not reduced extra chromosome material would be present making it lethal to the offspring. 6. Blue whales have 44 chromosomes in every cell. Determine how many chromosomes you would expect to find in the following: ” ”Sperm Cell: ” 22 chromosomes ”Egg Cell: ” 22 chromosomes ”Daughter Cell from Mitosis: ” 44 daughter cells ”Daughter Cell from Meiosis II: ” 22 daughter cells

Experiment 4: The Importance of Cell Cycle Control Data: 1. 2. 3. 4. 5.

Extra Chromosome - Klinefelter’s Syndrome-XXY Missing Chromosome - Turner’s Syndrome-Monosomy with X0 Chromosomal Deletion - Angelman Syndrome Translocated Chromosome - Robertsonian Translocation Lattice of networked cells - HeLa Cell

Post-Lab Questions ”1. Record your hypothesis from Step 1 in the Procedure section here. ” Cancer cells will appear irregular when compared to cells that undergo normal cell cycle. ”2. What do your results indicate about cell cycle control? ” Without cell cycle control many syndrome(s) and diseases evolve if not death. Some of the abnormal cycles visualized were hereditary and some not. ”3. 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 yet, but was effectively treated with a cocktail of cancer-fighting techniques. Is it possible for this person’s future children to inherit this cancercausing mutation? Be specific when you explain why or why not. ” No. The reason this cancer would not be inherited is because inherited traits are received from the germ cell. 4. Why do cells which lack cell cycle control exhibit karyotypes which look physically different than cells with normal cell cycle. ” Cell cycle control is a check and balance system to ensure that meiosis is transpiring as it should, when it doesn’t work it is reflected in the genetic material. When there is skewed material the karyotype will look different.

Lab 3 Mitosis and Meiosis

BIO201L

”5. What are HeLa cells? Why are HeLa cells appropriate for this experiment? ” HeLa cells are an immortal human cell line. This cell line is appropriate because it allows for indefinite experiments. ”6. Research the function of the protein called p53. What does this function do? Explain how it can affect cell cycle control. ” The function of protein p53 is to stop growth, repair DNA, or destroy the cell. If p53 fails it can cause cancer cells to grow and spread. ”7. 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 abnormality of chromosomes. The Philadelphia chromosome is what is called a translocation chromosome where chromosome 22 and 9 break and reattach to each other. The end result is chronic myeloid leukemia. Chromosome number 9 appears longer in the karyotype and chromosome number 22 appears shorter....