ex1_2007_key - Name: _____________________________ Student

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Name: _____________________________ Student ID:_________________ Page 1 Zoo 470 - Exam 1 - Spring 2007 February 27, 2007 This exam has a total of 6 pages and a total of 50 points . You will have 90 minutes to complete it. Please put your name and student ID on all pages. Good luck! 1. Provide brief definitions for each of the following ( 6 points ): a. capacitation: Process by which mammalian sperm become competent to fertilize an oocyte by virtue of being the female reproductive tract. b. Smad: Proteins activated by the TGF-b/BMP pathway. Smads transduce TGF-b signals to the nucleus by forming a complex that enters the nucleus to alter transcription. c. parthenote: An embryo formed by activation of the egg without a fertilizing sperm. In many cases, parthenotes further require that the first cytokinesis is suppressed to restore diploidy. d. compaction: Cadherin-dependent increase in adhesion of mammalian embryos at the 8-cell stage. e. fate mapping: Process by which cells in an early embryo are followed to see what progeny they make later in development. Fate mapping can involve applying bits of color to the exterior of the embryo, simply watching embryos carefully, or injection of a tracer into the cytoplasm of individual cells. f.: broadcast spawning: Process of gamete release often exhibited by aquatic species, in which large numbers of gametes are released, and gametes rely on chance encounters for successful fertilization. Sea urchins are an example. 2. MPF and cytostatic factor are known to regulate meiotic cell divisions. Answer the following questions, based on your knowledge of these factors' effects on cell division. a. If purified CSF were injected into one cell of a two-cell embryo immediately after first cleavage, what would you predict would happen at the time of the next division? Clearly state your reasoning. ( 1 point ) At the next division, the injected cell would arrest at metaphase, since CSF would stabilize MPF, preventing its breakdown. Name: _____________________________ Student ID:_________________ Page 2 2 (cont) b. Recall that frog eggs can be artificially activated by pricking them with a needle. What would you expect would happen to levels of MPF within a few minutes after pricking an egg? Clearly state your reasoning . ( 2 points ) Calcium elevation leads to CSF breakdown in such an oocyte, quickly leading to MPF inactivation (i.e., decrease in MPF activity) 3. You have isolated a gene that you believe encodes a novel sperm cell surface protein, headline , and you are making a presentation to a major pharmaceutical corporation for research support to work on this protein. a. You come to the presentation armed with the following pieces of data. For each of the following facts, state the technique(s) you used to obtain your data. ( 4 points ) Discovery Technique(s) Used for Discovery When viewed under the microscope, human sperm extracted from the epidydimis lack headline protein immunostaining The mouse headline mRNA has a size of 2.6 kB mRNA has a size of 2....
View Full Document

This note was uploaded on 08/08/2008 for the course ZOO 470 taught by Professor Hardin during the Spring '08 term at Wisconsin.

Page1 / 6

ex1_2007_key - Name: _____________________________ Student

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online