practice exam1 - Biology 240W Spring 2005 Exam 1 Version A...

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Biology 240W Spring 2005 Exam 1 – Version A 09 February Name: ______________________________ Userid: ____________________ Page 1 of 7 Remember to FILL IN THE EXAM VERSION AND YOUR STUDENT ID ON YOUR SCANTRON . There are 35 multiple-choice questions, each with one BEST answer. When you complete the exam return the test form and your scantron to you TA. Good luck!!! 1. You are developing a high resolution imaging system to perform non-invasive sex determination for pregnant couples by simply looking for morphological signs of genital development. When you pitch this idea to a venture capital firm, however, they laugh you out of their office when you proclaim your ability to determine the sex of a fetus at 4 weeks of gestation. Why did your presentation garner this response? a. Ovaries are visible at this stage, but testes are not so it would be impossible to definitively determine the sex of the fetus. b. Testes are visible at this stage, but ovaries are not so it would be impossible to definitively determine the sex of the fetus. c. At this stage, the gonads are in a bipotential phase so no sex-specific development has occurred. d. At this stage, gamete production in the gonads has begun, but ova and spermatozoa look the same so it would be impossible to determine the sex of the fetus. 2. If you want to ensure that a pregnancy results in a female child, which of the following molecular manipulations would you use? a. Activate receptor tyrosine kinase signaling pathway(s) in the embryo. b. Activate TGF β signaling pathway(s) in the embryo. c. Treat the embryo with testosterone. d. Activate Wnt signaling pathway(s) in the embryo. 3. How do the mechanism(s) employed by lipid derived signaling molecules (e.g. testosterone) differ from the mechanism(s) used by peptide-derived signaling molecules? a. Lipid hormones bind intracellular receptors while peptide derived signaling molecules bind cell surface receptors. b. Lipid hormones stimulate the production of second messengers in the cytoplasm while peptide derived signaling molecules lead to second messenger production in the nucleus. c. Lipid hormones can only act over small distances because they cannot be transported in the blood stream, whereas peptide hormones can easily travel throughout the circulatory systems. d. Lipid hormones are only involved in sex determination while peptide derived hormones are involved in a number of physiological processes. 4. If you collected spermatids from the lumen of the seminiferous tubules and tried to fertilize an ovum, would it work? Why or why not? a. No. Spermatids have not undergone spermiogenesis and, therefore, are not capable of fertilizing an ovum. b. No. Spermatids are still diploid and must complete meiosis before they are capable of fertilizing an ovum. c.
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This note was uploaded on 03/10/2008 for the course BIOL 240W taught by Professor Nelson,kimberlyn during the Spring '08 term at Pennsylvania State University, University Park.

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practice exam1 - Biology 240W Spring 2005 Exam 1 Version A...

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