Larsen's Human Embryology, 5th Edition Test Bank

Schoenwolf et al.: Larsen’s Human Embryology, 5th Edition Chapter 2: Second Week: Becoming Bilaminar and Fully Implanting Test Bank MULTIPLE CHOICE 1. A young child is diagnosed with Angelman syndrome, a syndrome in which a deletion occurs in a portion of the long arm of chromosome 15. Both Angelman syndrome and another syndrome involve the same deletion, but the two syndromes differ depending on whether the defect was inherited from the mother or father. What is the related syndrome? A. Prader-Willi syndrome B. Down syndrome C. Treacher Collins syndrome D. Branchio-oto-renal syndrome E. CHARGE syndrome ANS: A 2. A researcher inactivates the Sox17 gene in an animal model. As a result of this, one of the primary germ layers fails to form. What germ layer is most likely to be affected? A. Ectoderm B. Somatic mesoderm C. Splanchnic mesoderm D. Extraembryonic mesoderm E. Endoderm ANS: E 3. The early conceptus can spontaneously abort if it doesn’t implant into the uterine wall and develop a uteroplacental circulation. Which vessels of the embryo directly contribute to this essential circulation? A. Dorsal aortae B. Precardinal veins C. Vitelline arteries and veins D. Allantoic arteries and veins E. Postcardinal veins ANS: D 4. A 45-year-old woman who tests positive on a home pregnancy test is later diagnosed with a complete hydatidiform mole. What is unusual about the chromosomes of complete moles? A. All chromosomes are derived from the mother. B. All chromosomes are derived from the father. C. Roughly two-thirds of the chromosomes are derived from the mother. D. 23 chromosomes are present. E. 69 chromosomes are present. ANS: B 5. X inactivation is an example of which process? A. Imprinting B. Meiosis C. Mitosis D. Dosage compensation E. Oogenesis ANS: D