SergioDev't and NS (NO ANSWERS)

SergioDev't and NS (NO ANSWERS) - Fertilization Zygote...

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1 Fertilization  Zygote Cell Proliferation Differentiation Morphogenesis Apoptosis
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2 Differentiation: Maternal Effect Genes Differentiation--cells become  specialized to become one type  of cell (nerve, liver cell, etc).   HOW? Maternal effect genes  in  the egg encode for cytoplasmic  determinants (CDs), which are  unevenly distributed in the egg.  After fertilization and mitosis,  different cell nuclei are exposed  to different sets of CDs, the CD’s  cause different genes to be  turned on, as a result, the  totipotent cells become different  types of cells.
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3 The process of cellular differentiation (makes the cell specialized) is a direct result of A) morphogenesis. B) Cell proliferation C) apoptosis. D) cell division. E) differential gene expression
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4 Drosophila Fruit Flies Bicoid is a Cytoplasmic Determinant! Nurse cells supply the egg w/ nutrients and bicoid mRNA When the egg is UNFERTILIZED, the [ ] of bicoid mRNA is highest at the anterior end of the egg. Therefore, the anterior-posterior axis is specified before fertilization! As soon as the egg is FERTILIZED, mRNA is translated into bicoid protein . bicoid = head specific genes are turned on Moderate bicoid = thorax specific genes are turned on bicoid = tail specific genes are turned on
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5 A female and male fly mate. However, the resulting embryonic cell has a missing head and instead has tails on both ends. Which are correct? I. It’s the woman’s fault II. It’s the man’s fault III. Bicoid is missing inside the cell IV. Bicoid is found in both ends of the cell A) I and III B) I and IV C) II and III D) II and IV E) None of the above
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6 You experimentally control Bicoid protein levels so it is expressed evenly at moderate levels throughout a developing Drosophila embryo, what would you expect to see in the resultant larva? A) The head and tail ends will be switched B) Normal development, with no mutant traits C) Too many thoracic (chest) segments D) Both ends will have a tail E) Two heads on both ends
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7 Maternal effect, Segmentation, and Homeotic  genes Some maternal effect proteins like bicoid bind  to DNA and turn on segmentation genes Segmentation genes code for proteins that  develop into a particular segment For example, bicoid is a maternal effect protein  that binds DNA and turns on the segmentation  gene that codes for Hunchback protein, which  makes the anterior (head) segments of an  embryo After the segmentation genes have established  the number and orientation of the segments,  homeotic genes  become active and determine  the identity of individual segments.  The early steps in animal development differ  from flies, but the Hox genes (homeotic genes)  have been found in all animals
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8 In the Squarepants family of Bikini Bottom, a phenotype persists where everyone in the family has only four digits on
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This note was uploaded on 01/25/2011 for the course CHEM 1LB taught by Professor Edwards during the Fall '08 term at UC Irvine.

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SergioDev't and NS (NO ANSWERS) - Fertilization Zygote...

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