21 16 points 2 points each part male and female

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21. (16 points, 2 points each part) Male and female gametes are highly specialized cells. The following questions concern the similarities and differences that we have discussed pertaining to the gametes. A. What type of cell division is used to generate both male and female gametes? __________________________________________ One or more vesicle-like packets of enzymes and other proteins are located near the cell membrane of both sperm and egg cells. B. What is the name of the vesicle in a sperm? _________________________________________ C. What is the name of the vesicles in an egg? _________________________________________ D. What organelle makes all of these vesicles during gametogenesis? ______________________ During fertilization, the vesicle-like packets serve important functions. In the case of both gametes, it is the release (or exocytosis) of the packet contents at the right time and location that is vital. E. In 1-2 sentences, state the role the released contents of the sperm vesicle. In your answer, address both the sea urchin and mammalian sperm vesicle. F. Several molecules are released from egg vesicles. Overall, what is the major role of the released egg vesicle contents that is true for the eggs of many species? Use 1-2 sentences to state your answer. In some species like the sea urchin, the polymerization of actin in the gametes is used at discrete times during fertilization. Each gamete undergoes a physical change when actin polymerizes and a new structure is formed on the gamete. Below, name the structures that are formed: G. In the sperm, polymerization of actin forms ________________________________________ H. In the egg, polymerization of actin forms _________________________________________
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E-55, Exam 1-2010: Name Page 6 of 8 22. (6 points) Species have a number of ways by which to make their gamete cells compatible at a molecular level. In sea urchins, name four ways (i.e. molecular matches) that ensure gametes from the same species are brought together in the ocean. NOTE: In your response, we ARE NOT asking for you to name particular molecules like peptides but to indicate how gamete behavior and/or interactions are made species-specific. 1. 2. 3. 4. 23. (6 points) Kartagener syndrome in humans is characterized by several traits such as a propensity to respiratory tract infection and reversal of the left/right positions of the internal body organs (or situs inversus ). Males with Kartagener syndrome are also infertile. A mutation in the gene encoding dynein is the sole cause of the disease. Based on your understanding of fertilization, use 2-3 sentences to explain why the dynein protein is essential for male fertility. Clearly state the function of dynein in your answer. 24. (8 points) Sperm-egg binding is essential for successful fertilization. For each scenario below, indicate if fertilization will occur and provide 1 sentence that clearly states the reason why based on your understanding of sperm-egg interactions. Scenario 1: Sea urchin sperm that have not been exposed to egg jelly are incubated with sea urchin eggs that have been stripped of their jelly coat. FERTILIZATION? YES or NO (Circle your response) WHY? Scenario 2: Human sperm are extracted directly from the seminiferous tubule and added to a human oocyte for in vitro fertilization.
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