Student Outline Unit 8 - Reproductive System

Student Outline Unit 8 - Reproductive System - BIO 212...

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Kaplan SP 2010 Unit 8: Reproductive System 1. Vertebrate Development –General a. dynamic process b. c. at different sites, cells form organs d. growth allows the organism to survive after birth 2. Pathway of Vertebrate Development a. fertilization b. egg and sperm fuse to form one celled zygote c. cleavage - initial period of cell division 1. zygote divides 2. forms more and more smaller cells called blastomeres 3. no increase in overall size of the zygote 4. ends of the zygote are animal and vegetal poles a. animal pole forms external tissues b. vegetal pole forms internal tissues c. dorsal ventral sides determined by where sperm enters (belly) d. Blastula formation 1. 16 cell stage 2. cells pump salt into the cell spaces 3. water follows and a water filled ball results e. Gastrulation 1. one wall pushes in (collapsed tennis ball) 2. vegetal pole contracts on itself and pushes in (invaginate) 3. 4. 3 germ layers (ecto, meso, endoderm) a. b. mesoderm - muscles, bones, blood CT c. endoderm - stomach, lungs, liver, internal organs f. Neurulation 1. broad zone of ectoderm thickens on dorsal surface 2. pinches off and forms neural tube g. Cell Migration 1. cells move to form distant tissues h. 1. basic body plan is established 2. embryo is 10 5 cells and 3 mm long 3. will increase in size by 100 times and add 1 million cells 3. Mechanisms of Development a. determination 1. totipotent cells commit to a specialized developmental path 2. totipotent cell, transferred any where will develop like its neighbors b. determined cell 1. transferred any where, the cell will develop independent of its neighbors 2. activation of genes reinforce their own activity (deterministic) 3. can not be reversed
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c. differentiated 1. cell specialization at the end of the developmental path d. pattern formation - homeotic genes 1. master switches that code for proteins that function as transcription factors 2. homeobox = sequence of 180 bp that code for homeodomain 3. distinguishes parts of genome that code for pattern formation e. programmed cell death 1. cells die due to injury or damage = necrosis 2. cells programmed to die shrivel & shrink (apoptosis) a. their remains are taken up by surrounding cells 3. bax gene encodes the cell death program 4. bcl-2 oncogene suppresses cell death program a. bcl-2 prevents cell death by destroying free radicals b. antioxidants are almost as effective as bcl-2 protein in blocking apoptosis 4. Asexual and Sexual Reproduction a. Asexual 1. Budding 2. Fragmentation 3. Fission b. Sexual 1. Parthenogenesis 2. Hermaphroditic a. simultaneous vs. sequential 3. oviparous
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Student Outline Unit 8 - Reproductive System - BIO 212...

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