ex2_2009_key_final - Name Student ID Page 1 Zoology 470...

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Name: ______________________________________ Student ID:________________________ Page 1 Zoology 470 - Exam #2 – 2009 This exam has 6 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. 1. Provide concise definitions for each of the following ( 5 points ) a. Müllerian duct: Duct retained in female but not in male mammals. The Müllerian duct contributes to the formation of the oviduct/fallopian tube. b. blastocoel: A fluid-filled cavity formed during cleavage and prior to gastrulation. The blastocoel allows for the formation of an internal environment different from the external environment. c. reporter construct: DNA construct containing the promoter (regulatory DNA) of a gene of interest, fused to a “reporter”, such as GFP or lacZ, that produces a colored product in the places where the normal gene would be expressed. Useful for dissecting DNA regulator element important for the normal expression patterns of a gene. d. myogenic factor: Transcription factor important for muscle differentiation, which when overepxressed causes cells to differentiate as muscle. Examples include MyoD1, myf5, and MRF4. e. homeotic gene: Technically, any gene, which when mutated results in a transformation of a body part into another type of body part. Specifically, in Drosophila, gene encoding a homeodomain transcription factor required for proper segmental identity. The 3' to 5' order of homeotic genes on the chromosome corresponds to their anterior to posterior domain of action along the body axis. 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 Drosophila (fruit fly) centrolecithal meroblastic Not applicable Monkey (mammal) isolecithal holoblastic rotational Starfish (an echinoderm) isolecithal holoblastic radial Chicken (bird) telolecithal meroblastic discoidal Snail (a gastropod mollusk) isolecithal holoblastic spiral
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Name: ______________________________________ Student ID:________________________ Page 2 3. Circle true (T) or false (F) for each of the following ( 8 points ) T Humans, like other chordates, are deuterostomes F A weak mutation in the mouse pax-6 gene would be expected to result in loss of posterior structures, since the fly homologue is involved in patterning posterior segments of the embryo T The Wolffian duct is normally retained in male mammals F Proteins can act as transcriptional regulators or translational regulators, but not both F Embryos in which rapid cell division is occurring would be expected to engage in extensive morphogenetic movements at the same time F Primordial germ cell migration in vertebrates would be expected to be normal when excess SDF-1 is added T Enhancers are proteins that can act 5' ("upstream") or 3' ("downstream") to their associated gene
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ex2_2009_key_final - Name Student ID Page 1 Zoology 470...

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