Exam 3 (Final Exam) December 20, 2007

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1 Biology 4361 Exam 3 (Final Exam) December 20, 2007 Name: ID: Multiple choice (1 point each. Indicate the best answer.) 1. During Drosophila gastrulation, mesoderm moves in through the a. primitives streak. b. node. c. dorsal lip. d. ventral furrow. 2. During development of Drosophila eggs, the nurse cells a. contribute mrna to the egg. b. are joined to the egg by cytoplasmic bridges. c. donate cytoplasm to the egg. d. all of the above. 3. The gurken gene is synthesized by Drosophila nurse cells and is transported into the oocyte. This results in the posteriorization of the a. nurse cells. b. follicle cells. c. oocyte. d. none of the above. 4. Drosophila bicoid mrna binds to a. kinesin, which moves to the (-) end of the microtubules. b. kinesin, which moves to the (+) end of the microtubules. c. dynein, which moves to the (-) end of the microtubules. d. dynein, which moves to the (+) end of the microtubules. 5. In general, the hierarchical order of gene expression in early Drosophila development is a. Maternal Effect, Gap, Pair-rule, Segment Polarity. b. Maternal Effect, Pair-rule, Segment Polarity, Gap. c. Gap, Maternal Effect, Segment Polarity, Pair-rule. d. none of the above. 6. If you created a Drosophila embryo with a homeotic selector gene knockout, where might a typical phenotypic effect be found? a. anterior-posterior axis development. b. gastrulation. c. segmentation. d. wing development. 7. Chicks undergo a. bilateral cleavage. b. rotational cleavage. c. discoidal cleavage. d. syncytial cleavage. 1

2 8. During chick gastrulation, cells move into the blastocoel through a. the primitive pit b. the primitive groove. c. Hensen s node. d. all of the above 9. Gastrulation in mammals most closely resembles which of the following? a. reptiles b. amphibians c. sea urchins d. Drosophila 10. is seen as a hallmark of early mammalian development. a. Asynchronous cleavage b. Rotational cleavage c. Compaction d. all of the above 11. The portion of the trophoblast the erodes the uterine tissue is referred to as the a. cytotrophoblast. b. choriotrophoblast. c. syncytiotrophoblast. d. amniotrophoblast. 12. If expression of all copies of a particular Hox gene were knocked out, what would the expected result be regarding the identity of the affected region? a. The region would take on the identity of the next most anterior region. b. The region would take on the identity of the next most posterior region. c. The region would revert to a default identity (i.e. would not differentiate into any structure) d. none of the above. 13. Primary neurulation occurs in a. the anterior neural tube. b. the posterior neural tube. c. the entire neural tube. d. none of the neural tube. 14. Folding of the floor plate of the neural tube is facilitated by a. notochord cells. b. mesenchymal mesoderm. c. columnar epithelium cells. d. medial hinge point cells. 15. The force that closes the neural tube is supplied in part by the a. neural tube. b. epidermal ectoderm. c. both a and b d. neither a nor b 2

3 16. Anencephaly results form the failure of the to close. a. anterior neuropore b. posterior neuropore c. dorsolateral hinge points d. neural crest 17. Myelination is carried out in the peripheral nervous system by a. oligodendrocytes. b. glial cells. c. Schwann cells. d. dendrites. 18. The neural tube floor plate is primarily specified by a. BMPs b. Shh c. Nodal d. Notch 19. Trunk neural crest cells that migrate through the dorsolateral pathway a. migrate before those traveling through the ventrolateral pathway. b. migrate after those traveling through the ventrolateral pathway. c. migrate at the same time as those traveling through the ventrolateral pathway. d. prevent migration through the ventrolateral pathway. 20. The parasympathetic (enteric) ganglia of the gut are formed by a. cranial neural crest cells. b. trunk neural crest cells. c. vagal and sacral neural crest cells. d. cardiac neural crest cells. 21. During intramembranous ossification the osteoid matrix that binds calcium is formed by a. osteoblasts. b. osteoclasts. c. osteocytes. d. osteoforms. 22. In general, the major mesodermal lineages are determined by gradients of a. retinoic acid. b. sonic hedgehog. c. FGFs. d. BMPs. 23. In the process of mammalian somite formation, the clock for periodic somite formation is considered a. Notch. b. Fgf8. c. Hairy 1. d. none of the above 3

4 24. During somite formation, the paraxial mesoderm undergoes a. convergent extension. b. an epithelial-to-mesenchymal transformation. c. a mesenchymal-to-epithelial transformation. d. none of the above. 25. Which of the following bones are formed by endochondral ossification? a. inner ear. b. facial. c. wrist. d. all of the above. 26. What portion of the pronephric kidney is functional in the adult mammal? a. pronephros b. nephric duct c. nephrons d. none of the above 27. The mesonephric kidney supplies the adult mammal with which structures? a. vas deferens b. epididymus c. efferent ducts d. all of the above 28. The growth factor responsible for initiating angiogenesis is called a. FGF b. TGFβ c. BMP d. VEGF 29. The thymus gland is derived from a. branchial arch. b. pharyngeal pouch. c. pharyngeal arch. d. aortic arch. 30. Amniote eggs prevent desiccation by developing the a. amnion. b. chorion. c. allantois. d. yolk sac. 4

5 True / False (1 point each.) 31. Torso, the Drosophila terminal determinant, is a receptor tyrosine kinase. True / False 32. In chick embryos the endoderm layer is derived from the secondary hypoblast. True / False 33. Mammalian Hox genes are homologs of Drosophila homeotic selector genes. True / False 34. Neurons are guided to their ultimate destinations by oligodendrocyte cells. True / False 35. The mammalian brain is structurally organized both horizontally and vertically. True / False 36. All neural crest cells undergo epithelial-to-mesenchymal transformation. True / False 37. Cells destined to be tendons can be identified by the presence of the MyoD protein. True / False 38. The human face is primarily a product of neural crest cells. True / False 39. Cardiogenic mesoderm forms the heart and blood vessels. True / False 40. The foregut is derived from an outpocketing of the respiratory diverticulum. True / False Fill in. (1 point per answer) Use the terms from the Term Banks to make the most accurate sentence. Terms may be used more than once. Term Bank: Drosophila dorsal-ventral axis specification Cactus Dorsal dorsal Frizzeled Gurken nuclear Nudel Pipe Toll Torpedo Spätzle ventral In Drosophila the process of dorsal-ventral axis specification starts with protein expression in the dorsal region of the oocyte, where it binds to the receptor and blocks the expression of the protein. In the region, expression of starts a cascade of enzymatic activity that eventually causes the binding and activation of the receptor, which subsequently causes the activation of the transcription factor, which stimulates genes that specify fates. 5

6 Term Bank: Mammalian blastocyst derivatives allantois amnion blastocyst chorion cytotrophoblast decidua embryo hypoblast inner cell mass epiblast trophoblast syncytiotrophoblast The mammalian blastocyst is divided into two major portions: The, which will eventually form the embryonic portion of the placenta, is composed of the and. The embryonic placenta is referred to as the. The second portion of the blastocyst, the splits into the and the, with the former creating the and the latter forming the extraembryonic yolk sac. Short answer. (6 points each; answer any four.) Be as specific as possible and completely answer all parts of each question. 58. Two opposing gene activities specify the dorsal and ventral regions of the neural tube. List these genes and describe what portions of the neural tube that they specify. 59. Describe the role of gravity in determining the position of the primitive streak in chick embryos. 60. Describe the formation of intramembranous bone. 6

7 61. List the four major mesodermal lineages and provide one structure that arises from each one. 62. Describe the mechanism that veins and arteries use to connect to each other during angiogenesis; specifically, how do veins attach to arteries and avoid attachment to other veins? 63. Define the following terms dealing with mammalian early mammalian development: compaction, morula, cavitation. Short Essay. (Ten points each; answer any two) Be sure to address and completely answer all parts to the questions. 64. Describe the establishment of the anterior-posterior axis in Drosophila, specifically involving the bicoid, nanos, hunchback, and caudal genes and proteins. 7

8 65. Describe the formation of endochondral bone. 66. Drosophila embryos develop parasegments and segments. Describe how these are organized structurally and how they function in the adult organism. 8

9 67. Mammalian somites are periodic structures that form during embryogenesis. Describe in general terms what forms of gene or protein activities that would be necessary to create somites. Short Essay II. (15 points each. Answer any three.) 68. The establishment of the left-right axis has some similarities and some differences among different species. For two of the species that we have studied, describe the major gene(s), paracrine factors, or other proteins involved and describe how they operate structurally to establish the left and right sides. 9

10 69. Most of the model species we have studies have a certain region or structure referred to as an organizer. What does this term mean? What functional test would you use to determine whether a particular region or structure had organizer properties? For two of the models we studied, list the organizer structure or region. 70. Transformations of cells between epithelia and mesenchyme are very common during development. Describe one situation in which epithelial cells transform into mesenchyme and one in which mesenchymal cells transform into epithelia. Be specific regarding species, tissue, developmental stage, and the developmental process that the cells or tissue is undergoing. 10

11 71. Your task in the lab is to design experiments that will determine which migration pathway a certain set of neural crest cells takes, and where (or when) during their journey they become specified. Describe at least two experiments that use different techniques of experimental developmental biology that would address these questions. Be as specific as possible in your explanation of the experimental design and the possible results. 11

12 72. Describe one area or subject that we covered in the class that you feel needs further attention, clarification, or explanation. (2 pt.) 73. List one area or subject that you would like to see covered in more detail or one that we didn t discuss that you wish we had. (2 pt.) 74. List one fact that we covered that surprised, fascinated, or repelled you. (1 pt.) Bonus question. (1 pt.) Dr. James Thomson and Dr. Shinya Yamanaka recently made headlines by announcing what scientific discovery? Bonus bonus question. (1 pt). This is the second time that Dr. James Thomson has made the news in the last few years. What was his first newsworthy accomplishment announced in 1998? 12