BIOS Development

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BIOS Development
2013-12-01 15:33:35
Bios Development

BIOS Development mastering
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  1. Which of the following is not a body segment of the fruit fly embryo?   
    Antenna. The antenna is not a body segment of a fruit fly embryo.
  2. Which of the following statements about a gene that shows maternal effect inheritance is true?   
    Offspring will show a mutant phenotype if the mother has a mutant genotype. This statement is true; the gene is transcribed in the mother, and the mRNA is delivered to the zygote.      
  3. True or False? Pattern formation refers to events that organize embryonic cells in space   
    True. Pattern formation is the process by which the location of an embryo's body segments is determined.
  4. Where is bicoid mRNA translated?
    Fertilized egg. bicoid mRNA is translated at the anterior pole of the fertilized egg.
  5. Which body part develops in regions with a low concentration of Bicoid protein?   
    Abdomen.The regions with low concentrations of Bicoid protein develop into posterior structures such as the abdomen.
  6. Which of the following statements about the Bicoid protein is true?
    The Bicoid protein is a regulatory transcription factor. The Bicoid protein regulates expression of the embryo's early developmental genes.      
  7. If bicoid mRNA is injected at the anterior end of an egg from a bicoid mutant mother, what would the phenotype of the resulting larva be?
    The larva would be normal with one head at the anterior pole. The injected mRNA would rescue the mutant phenotype of the egg.
  8. A high concentration of bicoid protein at the opposite ends of a developing Drosophila embryo would result in the development of a _____.
    two-headed fly. The head develops where there is a high concentration of bicoid protein.
  9. The bicoid gene product is directly responsible for _____ in a developing Drosophila embryo.
    the establishment of the anterior-posterior axis. The concentration gradient of bicoid protein determines the anterior-posterior axis of a developing Drosophila.
  10. The region of a Drosophila embryo with the highest concentration of bicoid protein will develop into the _____.
    head. The head develops where there is a high concentration of bicoid protein.
  11. What triggers the translation of bicoid mRNA?
    fertilization of the egg  Fertilization of the egg triggers translation of bicoid mRNA.
  12. The bicoid gene is a type of _____ gene.
    egg-polarity. Egg-polarity genes are responsible for establishing the polarity of the egg.
  13. The region of a Drosophila embryo with a low concentration of bicoid protein will develop into the _____.   
    abdomen. The abdomen develops where there is a low concentration of bicoid protein.
  14. What process produces the gradient of bicoid protein in a fertilized egg?
    diffusion. Bicoid protein is produced at the anterior end and diffuses toward the posterior, resulting in a gradient.       
  15. Bicoid mRNA is translated in _____.
     the fertilized egg. Bicoid mRNA is translated in the fertilized egg.
  16. The bicoid gene is transcribed by _____.
    nurse cells. Nurse cells transcribe the bicoid gene.      
  17. In animal development, which of the following best describes the process of cleavage?
    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.
  18. What are the cells created by cleavage called?   
    Blastomeres. A blastomere is a cell created by cleavage division.
  19. Which of the following are the three germ layers contained in the gastrula?
    Ectoderm, mesoderm, endoderm. These are the three basic embryonic cell layers of all vertebrate embryos.
  20. Which of the following stages of development is defined by the three embryonic tissue layers (ectoderm, mesoderm, and endoderm)?   
    Gastrula Gastrulation is the process that leads to the formation of the gastrula, which contains the three embryonic tissue layers.      
  21. What happens to a cell during the process of differentiation?   
    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.).      
  22. 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?   
    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.
  23. 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.   
    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.