Questions on Chapter 50

Questions on - Animal Development Chapter 50 The development of form requires not only cell division and growth but also cell determination and

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Animal Development Chapter 50 The development of form requires not only cell division and growth but also cell determination and cell differentiation, pattern formation and morphogenesis Cell Differentiation is the process by which a cell becomes specialized to carry out specific functions. Cell determination includes the molecular events leading to cell differentiation. What determines that a cell becomes committed to a certain task/specialization? Characterize stem cells, and explain the difference between these cells and terminally differentiated cells Morphogenesis is the development of form and the progessive organization of tissues and organs which occurs through pattern formation In pattern formation, cells may communicate by signaling and involve planned cell migration. During planned cell migration, cells undergo changes in shape and apoptosis (programmed cell death) Gene Expression : Usually no genetic changes occur during cell determination and cell differentiation. Differentiated cells of an individual have the same genetic information although each cell type expresses a different subset of that information. This is called the principle of nuclear equivalence. Differential gene expression means that various types of differentiated cells express different subsets of their genes, which is responsible for variations in chemistry, behavior and structure Fertilization includes contact and recognition between egg and sperm, regulated sperm entry, activation of the fertilized egg, and fusion of egg and sperm pronuclei Fertilization: (Fig 50-1) involves four important steps: Contact and recognition: what happens during this period? Sperm entry is regulated: why is this important? Fertilization activates the egg: what events are triggered as a result? Once fertilized, sperm and egg pronuclei fuse which produces the diploid nucleus and initiates DNA synthesis Fertilization in echinoderms: sea stars and sea urchins differs in two major ways – what are they? Egg Coverings are very important in fertilization:
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In Echinoderms, what is the role of the vitelline envelope and the jelly coat in attracting sperm of the same species? How does this help with the prevention of interspecific fertilization? In mammals; there are two layers that surround the egg – one is noncellular, the other cellular. What are they? Is the role of the two layers comparable to the vitelline envelope and jelly coat in the echinoderm? Acrosome Reaction: In sea urchins, the acrosome reaction facilitates penetration of egg coverings. When sperm first contacts the egg, which ions move into the acrosome and cause it to disorganize? What do the proteolytic enzymes in the acrosome do to facilitate fertilization in sea urchins? Are there specific receptors involved in the sperm/egg interaction? In mammals the acrosome reaction is preceded by capacitation; what is
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This note was uploaded on 10/08/2010 for the course BIO 380 taught by Professor Martin during the Spring '10 term at Rutgers.

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Questions on - Animal Development Chapter 50 The development of form requires not only cell division and growth but also cell determination and

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