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30 Cards in this Set
- Front
- Back
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Gametes |
haploid reproductive cells |
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Development proceeds in ordered phases throughan animal’s life cycle |
– Fertilization – Cleavage – Gastrulation – Organogenesis |
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Fertilization |
occurs when a haploid sperm and eggcells fuse, forming a diploid zygote |
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polyspermy |
fertilization by more than one sperm |
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fertilization envelope |
which keeps awayadditional sperm |
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Cleavage |
The set of rapid cell divisions that takeplace in animal zygotes immediately after fertilization |
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embryogenesis |
Theprocess that makes a single-celled zygote into amulticellular embryo |
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blastomeres |
The cells created by cleavage divisions |
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blastula |
The embryo consists of a mass of blastomere cells |
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What Role Do Cytoplasmic Determinants Play? |
Cytoplasmic determinants are found in specificlocations within the egg cytoplasm
– They end up in specific populations of blastomeres. Cleavage initiates the step-by-step process that results in the differentiation of cells |
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Cleavage occurs in the mammalian... |
Oviduct – Connects the ovary, where the egg matures – To the uterus, where the embryo develops |
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Blastocyst |
Results from cleavage a specializedblastula consisting of two populations of cells |
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Trophoblast |
The external, hollow thin-wall that surrounds the inner cell mass (ICM) |
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Fate of the Trophoblast |
After the blastocyst embeds in the uterine wall, amixture of trophoblast and maternal cells form theplacenta |
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Fate of the inner cell mass (ICM) |
The ICM contains the cells that undergo gastrulationand develop into the embryo |
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Gastrulation |
Results in the formation of embryonictissue layers |
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Most early embryos have three primary tissue layers |
Ectoderm mesoderm endoderm |
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Gastrula |
extensive and highly organizedcell movements radically rearrange the embryoniccells into a structure |
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Blastopore |
Gastrulation begins with the formation of an opening |
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Ectoderm |
forms the outer covering of the adult body and the nervous system |
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Mesoderm |
gives rise to muscle, most internal organs, and connective tissues such as bone and cartilage |
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Endoderm |
produces the lining of the digestive tract or gut, along with some of the associated organs |
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Organogenesis |
– Process of tissue and organ formation – Begins once gastrulation is complete and theembryonic germ layers are in place |
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Notochord |
Functions as a key organizing elementduring organogenesis |
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Neural tube |
is the precursor to the brain and spinal cord |
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Somites |
formed by neural tubes mesodermal cellsbecome organized into blocks of tissues |
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Determination |
Somite cellsdifferentiate in response to signals from nearbytissues These signals diffuse away from cells in thenotochord, the neural tube, and nearby ectodermand mesoderm to act on specific populations oftarget cells in the somite |
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Myoblast |
Is a cell that is determined to become amuscle cell but has not begun producing muscle-specific proteins |
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MyoD |
Is the protein that causes muscle celldifferentiation MyoD is a regulatory transcription factor – It binds to enhancers upstream of muscle-specific genes |
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Cell Differentiation |
1. Fertilization triggers cleavage, resulting in a blastocyst 2. Blastocyst cell signals trigger gene cascades, resulting inpositional changes during gastrulation 3. During organogenesis, the notochord signals specificsomite cells to begin MyoD production, targeting thesecells as belonging to specific muscles 4. These muscle cells begin expressing muscle-specific proteins |
