POGIL Cell Biology Activity 7 – Meiosis/Gametogenesis Schivell MODEL 1: karyotype Meiosis Mitosis 1 POGIL Cell Biology Activity 7 – Meiosis/Gametogenesis Schivell MODEL 2, Part 1: Spermatogenesis The trapezoid below represents a small portion of the wall of a "seminiferous tubule" 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 sperm This portion shown expanded in part 1 of Model 2 3 POGIL Cell Biology Activity 7 – Meiosis/Gametogenesis Schivell MODEL 3: Oogenesis This is a time lapse of an ovary showing one "follicle" as it develops from immaturity to ovulation. The follicle starts in panel 1 as a small sphere of "follicle cells" surrounding the oocyte. In each panel, chromosomes within the oocyte are shown as an inset. (There are actually thousands of follicles in each mammalian ovary). 1 2 3 4 5 6 7 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 chromosome. 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 female parent. These two chromosomes carry the same genes! (But can have different alleles on each homolog.) 4. For this organism, 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 mitosis? 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° Spermatocyte – 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 spermatocytes - Spermatid – 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 reproductive system 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 function 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 oocytes change over the 7 panels? _____________________ How does the number of follicle cells change over the 7 panels? __________________ 18. What type of cell division 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 protein, 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 "polar body". 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 spermatids 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 animal 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 species of ant in which males are haploid, females 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 _______________ _________________________________________ 7 .