2011Practice Exam 1d

2011Practice Exam 1d - BSC 2011 1 As an embryo develops new...

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UNIT I PRACTICE EXAM 1d 1. As an embryo develops, new cells are produced as the result of _____. A) differentiation. B) preformation. C) cell division. D) morphogenesis. E) epigenesis. 2. During fertilization, the acrosomal contents _____. A) block polyspermy. B) help propel more sperm toward the egg. C) digest the protective coat on the surface of the egg. D) nourish the mitochondria of the sperm. E) trigger the completion of cell division by the sperm. 3. Contact of an egg with signal molecules on sperm causes the egg to undergo a quick _____. A) cleavage. B) membrane depolarization. C) cortical reaction. D) release of enzymes. E) reaction. 4. From earliest to latest, which of the following choices lists developmental stages in the correct sequence? A) gastrulation -organogenesis -cleavage B) ovulation-gastrulation -fertilization C) cleavage-gastrulation-organogenesis D) gastrulation-blastulation-neurulation E) morphogenesis-neurulation-gastrulation 5. The vitelline layer of the sea urchin egg _____. A) contains cortical granules. B) releases calcium, which initiates the cortical reaction. C) has egg cell membrane receptor molecules that are specific for binding acrosomal proteins. D) is first visible only when organogenesis is nearly completed. E) is a mesh of proteins crossing through the cytosol of the egg. 6. The "slow block" to polyspermy is due to _____. A) a transient voltage change across the membrane. B) the consumption of yolk protein. C) the jelly coat blocking sperm penetration. D) formation of the fertilization envelope. E) inactivation of the sperm acrosome. 7. As cleavage continues during frog development, the size of the blastomeres _____. A) increases as the number of the blastomeres decreases. B) increases as the number of the blastomeres increases. C) decreases as the number of the blastomeres increases. D) decreases as the number of the blastomeres decreases. E) increases as the number of the blastomeres stays the same. 8. The dorsal-ventral axis of a frog embryo is established by signals arising from the _____. A) morula. B) primitive streak. C) archenteron. D) gray crescent. E) blastocoel. 9. The vegetal pole of a frog zygote differs from the animal pole in that _____. A) the vegetal pole has a higher concentration of yolk. B) blastomeres arise only in the vegetal pole. C) cells at the vegetal pole cannot divide completely. D) the vegetal pole cells undergo cell division more rapidly. E) blastomeres arise only in the animal pole. 10. An embryo with meroblastic cleavage, extra-embryonic membranes, and a primitive streak must be that of _____. A) an insect. B) a fish. C) an amphibian. D) a bird. E) a sea urchin. 11. If gastrulation was blocked by an environmental toxin, then _____. A) cleavage would not occur in the zygote.
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This document was uploaded on 11/03/2011 for the course BIO bsc2011 at FSU.

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2011Practice Exam 1d - BSC 2011 1 As an embryo develops new...

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