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Home , Karyotype, Meiosis

POGIL Activity 7 – / Schivell

MODEL 1:

Meiosis

Mitosis

1 POGIL Activity 7 – Meiosis/Gametogenesis Schivell MODEL 2, Part 1: The trapezoid below represents a small portion of the wall of a "" within the testis. The cells in each of the panels are all originally derived from the single cell in panel 1.

1 2 3 Outside of tubule

Lumen of tubule 4 5 6

7 8 9

2 POGIL Cell Biology Activity 7 – Meiosis/Gametogenesis Schivell MODEL 2, Part 2:

vas epididymis deferens

testis (plural: testes)

seminiferous tubules (cut)

Courtesy of: Dr. E. Kent Christensen, U. of Michigan

lumen of seminiferous tubule

This portion shown expanded in part 1 of Model 2

3 POGIL Cell Biology Activity 7 – Meiosis/Gametogenesis Schivell MODEL 3: This is a time lapse of an showing one "follicle" as it develops from immaturity to . The follicle starts in panel 1 as a small sphere of "follicle cells" surrounding the . In each panel, within the oocyte are shown as an inset. (There are actually thousands of follicles in each mammalian ovary).

1 2

3 4

5 6

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4 POGIL Cell Biology Activity 7 – Meiosis/Gametogenesis Schivell Model 1 questions: 1. Using the same type of cartoon as model 1, draw an "unreplicated", condensed .

2. Draw a replicated, condensed chromosome:

3. Circle a homologous pair in the karyotype. Remember that one of these chromosomes came from the male parent and the other from the parent. These two chromosomes carry the same ! (But can have different on each homolog.)

4. For this , its chromosome number is 2N= _____.

5. Label every cell in Model 1 as either diploid (2N, two homologs of each chromosome) or haploid (1N, one homolog of each chromosome).

6. Label each cell in Model 1 as having either replicated (R) or unreplicated (U) chromosomes.

7. What do homologs do during meiosis that does not occur during ?

8. List two differences between the final products of mitosis and meiosis:

______

Model 2, part 1 questions:

9. Does meiosis or mitosis occur between panels 1 and 2? ______

10. Follow the darkly outlined cell from panels 2 through 7. a. Are these cells going through meiosis or mitosis?______

b. Describe these cells' movement in the wall of the tubule over time:

11. Draw in the chromosomes in their proper states in the unfilled cells in panels 7-9 (except for the differentiated sperm - shaded).

12. Label cells in various panels of Model 2 with the best choice from the definitions below.

- 1° – sperm precursor, it is going through Meiosis I - 2° Spermatocyte – sperm precursor, it is going through Meiosis II - Spermatogonium – stem cell, it divides to produce new - – sperm precursor, it has completed Meiosis - Sperm – fully differentiated cell

13. Suggest a reason why both of the daughter cells of the division in panel 1-2 do NOT continue on through the same process. (Hint – think of the reproductive lifespan of males.)

5 POGIL Cell Biology Activity 7 – Meiosis/Gametogenesis Schivell Model 2, part 2 questions: 14. In which part of the male are sperm made? (Circle ONE)

vas deferens epididymis testis

15. Consider both parts 1 and 2 of Model 2. What is the relevance of the location of sperm differentiation?

16. Describe the path of sperm travel using the terms in part 2.

Your TA will discuss the of the epididymis in the gametogenesis lab.

Model 3 questions: 16. In panel 1, there are two types of cells shown in the follicle, one large one surrounded by many smaller ones. Shade the large one. This is the developing oocyte. The smaller ones are called "follicle cells".

17. How does the number of change over the 7 panels? ______

How does the number of follicle cells change over the 7 panels? ______

18. What type of is the oocyte going through? ______

Assuming follicle cells all have the same identical set of chromosomes, what type of cell division are the follicle cells going through? ______

19. Follicle cells surrounding the oocyte transfer , mRNA and nutrients into the oocyte, which in turn grows larger. Suggest a reason for this intensive "stockpiling" of resources in the oocyte.

20. Starting at panel 4, a fluid is being released into increase the size of the follicle. Which type of cell is most likely responsible for the release of this fluid? ______

21. a. Panel 7 shows ovulation. Has the released oocyte completed meiosis? ______

b. Meiosis I produced 2 daughter cells, but only one cell received cytoplasm and organelles. The other daughter is a "". Will the polar body survive? ______

c. Compare to spermatogenesis: Is the released oocyte a 1° or 2° oocyte? ______

d. Suggest a reason for the huge increase in fluid volume in the follicle prior to ovulation.

6 POGIL Cell Biology Activity 7 – Meiosis/Gametogenesis Schivell On Your Own:

1. Go back to model 2, part 1. List three things that change when develop into differentiated sperm.

______

2. Compare spermatogenesis with oogenesis. List three things that are different between the two processes.

______

3. In the cell to the right, a cell from a diploid is in the process of dividing. a. This cell is completing… (Circle one)

mitosis meiosis I meiosis II b. The 2 daughter cells produced by this cell division are: (Circle one)

haploid diploid c. This cell comes from a of ant in which males are haploid, are diploid.

i. This cell is taken from a... (Circle ONE) female male either

ii. Spermatogenesis in this species must require.... (Circle ONE) mitosis meiosis

4. For each cell below, write whether it is haploid (1N) or diploid (2N) and then write in where you can find that cell within a mammal (be as specific as you can).

Cell 1N or 2N? Location? a. Follicle cell ______b. 1° spermatocyte ______c. 2° oocyte ______d. mature sperm ______

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