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30 Cards in this Set
- Front
- Back
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fertilization
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is the fusion of two gametes to form the Diploid Zygote
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4 parts of sperm
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head, neck, midpiece, tail
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2 characteristics of animal cel
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1 highly specialized
2 large size |
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cortical granules
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small vesicles docked on the plasma membrane
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vitelline envelope
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fibrous, matlike sheet of glycoproteins that surrounds the egg
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jelly layer
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a large, gelatinous mass that also encloses the egg
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layers of the egg (from outside to inside)
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jelly layer, vitelline envelope, plasma membrane
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what is inside the egg?
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corticle granuales, yolk granules, nucleus
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why do scientists choose sea urchins to study gametes?
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1 they produce an enormous number of gametes
2 undergo external fertilization |
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acrosomal process
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penetration of the sperm through the jelly layer and the sperm nucleus and centriole enter the egg
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Fertilizin
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a compound on the surface of sea urchin egg cells that binds
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bindin
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protein on the head of sea urchin sperm
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what does the fusion of the sperm into the egg cause?
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1 sharp increase in Ca++ in the cytosol
2 stimulating fusion of the cortical granuals with the plasma membrane 3 this leads to building of the fertilization envelope also sweeps all other sperm away so not more than one can come |
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three segments of insect
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head, thorax, abdomen
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forward genetics
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mutated genes
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reverse genetics
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knock-out genes
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Experiements to see where bicoid protein is
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1. used dna fragments
2 used bicoid antibodies |
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conclusion of bicoid experiements
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bicoid produces an anterior-posterior concentratino gradient
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The Bicoid protein definition
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regulatory transcription factor that activates
genes required for anterior structures |
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Bicoid
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an example of a maternal effect gene
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cytoplasmic determinants:
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molecules found in the egg that helps direct early development.
These determinants affect development independently of sperm or zygote genotype |
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Antp
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dominant gain of function allele
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Ubx
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loss of function allele
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hox code
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gene code in the vertebrae
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Hox clusters
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ancient genome duplications, multiple of them in the vertebrae
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Antp expressed in a specific segment signals thoracic segment identity
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produce a leg
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Antp expressed in any area that is not specific to where it is suppose to
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terminate a leg
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mouse hoxb6 is homologous to
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antp
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homologous
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descent from common ancestor
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ORGANIZERS
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cells that have the ability to organize host and donor tissue into a second embryo
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