BIO1010 Lab 5 Mitosis and Meiosis S8 Fall16 PDF

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Lab prof. Joseph...

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Section S

Biology 1010: Fall 2016 Laboratory Five: Mitosis and Meiosis Directions: There is no simulation for this lab report. Completion of this lab report will be based on pdf file entitled Lab 5 Handout: Mitosis and Meiosis posted on LaunchPad. Please read the lab 5 handout and only answer the questions listed below for each activity. This lab report will provide extra hints and will decrease the number of questions for you to answer. Thinking about all the questions in the pdf will help you study for your final exam, and in reviewing all of chapter 6, but your lab report will only be graded on the questions below. Type the answers in complete sentences. Activity 1: Inquiry Questions 1. If an organism has a diploid chromosome number of 38 and goes through mitosis, how many chromosomes will be present in each of the daughter cells? (0.25 pts) There will be 38 chromosomes in each of the daughter cells.

2. What are the three main functions of mitosis? (0.25 pts) The three main functions of mitosis include growth of the organism, repair (such as wound healing), and replacement (such as blood cells).

3. A company has created what they call “the best lawn ever” using a new type of grass that has a mutation in mitosis. They plan to market it as the lawn you never have to mow. Do you think that a plant that cannot go through mitosis is a good investment? Why or why not? (0.5 pts) A plant that cannot go through mitosis is not a good investment because it would not be able to survive long unless it reproduces. However, the offspring would not be able to undergo mitosis, therefore it would not be able to develop since without the process of mitosis it cannot grow, replace, or repair.

Activity 2: Data Collection and Inquiry Questions

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Section S 1. Based on Table 7-1 and Figure 7-5, either write the name of the step or a description of the event on the blank line: (0.25 pts each/1.5 total)

Name of Event

Description of the Event

a. Prophase

Stage when individual chromosomes are first seen

b. Cytokinesis

Cytoplasm is divided into two daughter cells

c. Anaphase

Stage when chromosomes move towards the poles

d. Metaphase

Chromosomes line up in the center of the cell

e. Daughter cells

Cells not undergoing division

f. Telophase

Stage when there is formation of a new cell wall

2. In each of the 8 photographs in Figure 7-6 through 7-9 label a minimum of 30 cells/photograph, with either an I (interphase) or P, M, A or T, indicating the mitosis stage for those cells in the process of dividing. Then tally up the number of cells in each stage and record your results in table 1. Count only those cells in which a nucleus or chromosomes are visible. You MUST turn in your labeled photos to receive any credit for your cell counts. (4 pts)

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TABLE 1: NUMBER OF CELLS IN EACH STAGE YOU HAVE COUNTED Figure 7-6 a 7-6 b 7-7 a 7-7 b 7-8 a 7-8 b 7-9 a 7-9 b

Interphase 56 52 52 50 51 32 36 44

Prophase

Metaphase

Anaphase

Telophase

1 1 1 1 1 1 1 0

1 1 2 2 1 2 0 2

0 0 1 1 1 0 0 0

1 1 1 1 0 1 1 2

Total in all figures

373

7

11

3

8

3. Using your data Table 1, answer the questions below: (0.25 pts each/0.5 total) a. Which stage of MITOSIS takes the longest amount of time to complete? Interphase takes the longest amount of time to complete.

b. How did you determine this? What occurs in this stage? Interphase is the stage where chromosomes replicate in preparation for mitosis. This is when the cell grows and it takes the longest amount of time to complete because the cell spends most of its life in this stage waiting to divide again.

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4. If you examined the tip of a branch of an oak tree on campus in December and then again in April, would you expect to see the same rates of mitosis? Explain your answer. (1 pt) No, you would not see the same rates of mitosis in December as you would in April because in December, trees do not grow new leaves and mitosis is slowed down but in April, trees grow new leaves and mitosis is sped up.

Activity 3: Inquiry and Analysis 1. Using Figure 7-11, both a and b, answer the following questions: (1.5 pts) Question Are the daughter cells produced in this process identical to or different from each other? Are the daughter cells produced identical to or different from the PARENT cell? If the parent cell in figure 7-11 had 46 chromosomes how many would be present in each daughter cell?

Mitosis identical

Meiosis different

identical

different

46

23

Activity 4: Graph and Inquiry Questions 1. Create a graph using the information in Table 7.3. Your graph should have a title, and all of its axes properly labeled. (3 pts)

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2. As the number of chromosome pairs increase what happens to the number of possible gametes? (0.5 pts) As the number of chromosome pairs is increased by 1, the number of possible gametes is doubled.

3. Based solely on random assortment, how many possible different genetic combinations exist: a. When a human egg is produced by meiosis? When a human sperm is produced by meiosis? (0.5 pt) When a human egg is produced by meiosis, 8,388,608 possible different genetic combinations exist. When a human sperm is produced by meiosis, 8,388,608 possible different genetic combinations also exist.

b. What about for an egg and a pollen grain of banana (diploid # chromosomes = 20)? (0.5 pt) When an egg and a pollen grain of banana are produced by meiosis, 1,048,576 possible different genetic combinations exist.

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4. Joan and Alex Smith have five daughters who are quite different in appearance and talents. Discuss why this occurs based on the 2 events in meiosis that increase genetic diversity. (1 pt) Two events that occur in meiosis that increase genetic diversity are crossing over and independent assortment. Crossing over is the process where homologous chromosomes exchange corresponding segments of their genetic material to form recombinant chromosomes. This shuffles genetic information and increases variation. Independent assortment occurs when the maternal and paternal sister chromatid pairs are pulled to the ends of the cell randomly. The resulting pairs of sister chromatids are a mix of both the maternal and paternal sister chromatids therefore it increases variation.

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