Biology Exam 4: Chapter 47 – Flashcards
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In animal development, which of the following best describes the process of cleavage?
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Mitosis
***Cleavage refers to the rapid cell division that takes place in animals after fertilization. Cleavage partitions the egg cytoplasm without additional cell growth taking place.
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What are the cells created by cleavage called?
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Blastomeres
***A blastomere is a cell created by cleavage division
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Which of the following are the three germ layers contained in the gastrula?
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Ectoderm, mesoderm, endoderm
***These are the three basic embryonic cell layers of all vertebrate embryos.
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Which of the following stages of development is defined by the three embryonic tissue layers (ectoderm, mesoderm, and endoderm)?
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Gastrula
***Gastrulation is the process that leads to the formation of the gastrula, which contains the three embryonic tissue layers.
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What happens to a cell during the process of differentiation?
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It undergoes a change toward a more specialized form or function.
***During organogenesis, embryonic cells become progressively more specialized as they develop into their specific cell type (brain, muscle, etc.).
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A child is born without a fully developed pancreas. He is normal in all other respects, and thus doctors believe that the problem most likely began early in development. During which of the following processes did the original error most likely occur?
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Endoderm formation
***The endoderm provides the cells that develop into the lining of the digestive and respiratory tracts, as well as the liver and pancreas. Problems with its formation could result in an unformed pancreas.
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True or false? Early animal development progresses through distinct stages: first the production of the zygote through fertilization, then cleavage, then the formation of the gastrula, and then the formation of the blastula.
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False
***The formation of a gastrula is the last stage in early animal development; the zygote undergoes cleavage to form a blastula, which eventually forms a gastrula.
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During gastrulation in frogs, a rod of mesoderm under the dorsal surface forms the _____.
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notochord
This rod of mesoderm forms the notochord, a physically supportive structure.
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During gastrulation in frogs, cells from the animal pole spread over the embryo and form the _____.
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ectoderm
***Cells from the animal pole form the ectoderm.
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The notochord functions as a core around which mesodermal cells form the frog's _____.
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backbone
***In vertebrates, the notochord functions as a core around which mesodermal cells form the frog's backbone.
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An ectodermal thickening above the frog's notochord forms a _____.
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neural plate
***The ectodermal thickening above the frog's notochord forms the neural plate.
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The _____ is(are) formed when the neural folds join and a portion of the neural plate sinks beneath the embryo's surface.
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neural tube
***The question describes the formation of the neural tube.
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The enlarged anterior portion of the neural tube will develop into a frog's _____.
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brain
***The anterior end of the neural tube develops into the brain.
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The posterior portion of the neural tube will develop into the frog's _____.
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spinal cord
***The posterior portion of the neural tube develops into the spinal cord.
