NAME ___________________________ 1 BIOLOGY 205/SECTION 7 DEVELOPMENT- LILJEGREN Final Examination – April 29, 2009 Write your name at the top of each page. Read each question carefully before answering—i.e. read the instructions. In all answers, be as specific as possible, while respecting the amount of space allotted for each answer. Use of calculators and cell phones is prohibited during the exam. No regrades will be made on exams done in pencil. Be sure to sign and abide by the honor code pledge. ---------------------------------------------------------- 1.) (8 pts) It’s important to remember that proteins have specific jobs to do in the cell. For each protein below, indicate which of the following categories best describes its job: (Some categories may not be used.) a. Transcription factor e. Secreted signal b. Transmembrane receptor f. Homeodomain transcription factor c. Membrane-bound signal g. Transmembrane channel protein d. MADS-domain transcription factor h. Chromatin binding protein Polycomb _________________ Ultrabithorax __________________ MOM-2 __________________ Pax3 __________________ LET-23 __________________ APETALA3 __________________ LEAFY __________________ Delta __________________ 2.) (1 pt) One global mechanism of regulating gene expression involves the post- translational modification of __________________ proteins associated with DNA. 3.) (10 pts) We discussed how the fly body plan is specified by a cascade of genes during embryonic development. For each of the functions described below (which are NOT shown in order), name which gene category it represents, and name ONE actual gene in that category selected from the following list. Porcupine Antennapedia Raspberry Butthead Bald Fushi tarazu Mastermind Bicoid Krüppel Distalless Wingless Distorted Function Category A gene in this category Set up crude subdivisions ____________________ _____________________ Define anterior/posterior regions ____________________ _____________________ of segments Form more refined segments ____________________ _____________________ Specify segment identity ____________________ _____________________ Establish anterior/posterior axis ____________________ _____________________NAME ___________________________ 2 4.) (2 pts) Which organism(s) uses DNA methylation as a mechanism to regulate gene transcription? (A) Mouse (B) C. elegans Write letter(s) here _______ (C) Zebrafish (D) Drosophila (E) All of the above 5.) (2 pts) Hunchback is normally expressed in the segments of the fly embryo that will become the head. (Circle one) Is it likely to be turned ON or OFF by high levels of Bicoid? (Circle one) Is translation of Hunchback mRNA likely to be PROMOTED or BLOCKED by high levels of Nanos? 6.) (3 pts) We’ve talked about the key contributions of several scientists to our understanding of development. Match the names of the following scientists to their respective discoveries. (A) Sidney Brenner (E) Elliot Meyerowitz (B) John Bowman (F) Mario Capecchi (C) John Sulston (G) Ed Lewis (D) Christiane Nüsslein-Volhard (H) Thomas Hunt Morgan _____ characterized the first fly mutant _____ developed gene targeting in ES cells _____ pioneered use of Arabidopsis as a model organism 7.) (2 pts) The relationship of the Steel protein to the White-spotting (=Kit) protein is like which of the following relationships: (A) LET-23 to LAG-2 (B) Notch to Delta Write letter(s) here _______ (C) LIN-3 to LIN-12 (D) LAG-2 to LIN-12 (E) LIN-12 to LET-23 (F) LIN-3 to LET-23 (G) LAG-2 to LIN-3 8.) (1 pt) We discussed several mechanisms by which cells remember the decisions they make. What mechanism is affected by treating cells with azacytidine? ___________________________________________________________________NAME ___________________________ 3 9.) Determination and Differentiation are key concepts in understanding how individual cells follow instructions that allow them to develop uniquely and carry out specialized functions in a multicellular organism. a.) (3 pts) Define these two concepts and explain how they differ: b.) (2 pts) Describe the experimental results obtained by Hans Spemann and explain why they demonstrated the timing of determination during newt gastrulation. c.) (2 pts) Which of the following proteins specifically affects the determination of animal cells to become muscle? (A) MyoD (B) Hox3.1 Write letter(s) here ________ (C) Pax3 (D) Myf5 (E) Myogenin d.) (2 pts) What are two differentiated cell types found in plants? 10.) (10 pts) For each statement, circle T or F. For any that are false, indicate briefly why in the space below. a. T F Methylation of DNA shows a negative correlation with gene expression. ____________________________________________________________________ b. T F The C. elegans LIN-12 protein is related to the fruit fly Delta protein. ____________________________________________________________________ c. T F Mutations in the C. elegans ced-3 gene prevent programmed cell death. ____________________________________________________________________ d. T F Mutations in the mouse Bmp7 gene prevent ear and kidney development. ____________________________________________________________________ e. T F To initiate X chromosome inactivation, Xist proteins coat the inactive X chromosome. ____________________________________________________________________NAME ___________________________ 4 gonadanchorcell1° cell2° cell2° cell3° cell3° cell3° cellMake vulvaNormal hypoderm= skinNormal hypoderm= skin11.) (9 pts) The diagram shows the cell fates chosen by different cells of the vulval equivalence group in a wild-type worm. How many 1° cells, 2° cells, and 3° cells will be made in the cases listed below? a) In a wild-type worm 1° _____ 2° _____ 3° _____ b) In a worm in which the central two vulval precursor cells are ablated 1° _____ 2° _____ 3° _____ b) In a worm in which all the gonad cells are ablated 1° _____ 2° _____ 3° _____ c) In a worm with a homozygous loss-of function mutation in the LET-23 protein (total=six) 1° _____ 2° _____ 3° _____ e) In a worm with a homozygous gain-of-function mutation in the
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