01:119:116 Lecture Notes - Lecture 16: Model Organism, Microtubule, Plasmogamy
17 Jun 2020
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Document Summary
Development: changes that occur during entire life cycle of an individual includes embryonic and development following birth or hatching. Model organisms= species chosen for research because they are easily studied in the lab. Development occurs at many points in animal"s life cycle but we will focus on embryonic development fertilization through birth/hatching: fertilization. Fertilization= formation of a diploid zygote from a haploid sperm and egg (larger, immotile) Egg surrounded by plasma membrane and one or more coverings aid in fertilization by sperm of same species but barrier to interspecific fertilization (other species) >determines sex in many organisms (x or y sperm) >activates egg and stimulates development to take place. >sperm dissolves into protective layers around egg to each plasma membrane. >sperm surface molecules bind receptors on egg surface---> same species. >surface of egg changes to prevent polyspermy only one sperm enters. Will describe fertilization in sea urchin and mammals: fertilization in sea urchin: sperm entry, sea urchin a model organism.
