ex2_2006_key - Name: _ Student ID:_ Page 1 Zoology 470 -...

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Name: ______________________________________ Student ID:________________________ Page 1 Zoology 470 - Exam #2 – 2006 This exam has 5 pages and a total of 50 points . You will have 90 minutes to complete it. Answer all short answer questions as briefly as possible. Make sure your name and ID number are on all pages. You will receive 1 point for doing so. 1. Provide concise definitions for each of the following ( 6 points ) a. Wolffian duct: Tubular structure that is retained in male mammals. It becomes portions of the male reproductive tract, including the vas deferens. b. midblastula transition: Transition that occurs at different times in different organisms, but is accompanied by randomization of cell division, and a large-scale transition from reliance on maternal transcripts to production of zygotic transcripts. c. ectoderm: Most exterenal of the three primary germ layers. Ectodermal fives rise to tissues such as epidermis and neural tissues. d. contractile ring: Actomyosin-based structure that is responsible for pinching daughter cells off during cytokinesis. The CR is found at the cleavage furrow. e. invagination: Inward bending of sheet of tissue . f. maskin: Protein involved in general suppression of translation from maternal mRNAs. Following fertilization, changes in a complex of protein, including maskin, regulates the accessibility of the 3'UTR of maternal t5ranscreotis to the translational machinery. 2. Complete the following table referring to cleavage patterns in early embryos of various animals ( 5 points ) Animal Yolk Distribution Completeness of Cleavage Orientation of cleavages Squid (cephalod mollusk) telolecithal meroblastic bilateral Chimpanzee (mammal) isolecithal holoblastic rotational Earthworm (annelid) isolecithal holoblastic spiral Salamander (amphibian) mesolecithal holoblastic radial Turtle (reptile) telolecithal meroblastic discoidal 3. Circle true (T) or false (F) for each of the following ( 7 points )
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Name: ______________________________________ Student ID:________________________ Page 2 F Androgen insensitivity syndrome occurs in individuals who are genetically XY but who cannot make testosterone (don't have functional receptors) T Protein gradients as a patterning mechanism are possible in Drosophila because the early embryo is syncytial F oskar would be expected to be a zygotically acting gene, since it encodes a gene product required for germ cell formation in Drosophila embryos (acts maternally) F Genes can be transcriptionally regulated or translationally regulated, but not both ( Hunchback in flies disproves the statement!) F Presumptive endodermal cells in C. elegans are internalized via convergent extension ( they ingress) T Transcription factors can increase or decrease the rate of transcription of the genes they regulate T Testosterone is made in both male and female mammals (converted to estrogen in females) F
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This note was uploaded on 04/07/2009 for the course ZOO 470 taught by Professor Hardin during the Spring '08 term at University of Wisconsin.

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ex2_2006_key - Name: _ Student ID:_ Page 1 Zoology 470 -...

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