Biochemistry 3381A Study Guide - Quiz Guide: Spindle Apparatus, Cyclin B, Cyclin-Dependent Kinase 1
27 May 2020
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Document Summary
Cleavages: the first mitotic divisions of the zygote. Cleavages are a series of relatively fast divisions where the big zygote is divided into smaller daughter cells = blastomeres. No growth in cytoplasm occurs between cleavages. Cleavages are controlled by proteins and mrnas that are stored in the egg cytoplasm. The cell cycle is regulated by mitosis-promoting factor (mpf) In later stages, additional cyclins are synthesized which can bind and add the gap stages to the cell cycle: at that time the synchronicity of cell divisions gets lost. Karyokinesis: mitotic division of the nucleus (managed by microtubules of the mitotic spindle) Cytokinesis: division of the cell (managed by actin filaments forming a contractile ring) Karyokinesis without subsequent cytokinesis leas to the formation of a syncytium. Holoblastic cleavage holoblastic=complete cleavage: isolecithal: low amount of yolk, evenly distributed, mesolecithal: medium amount of yolk, more yolk at the vegetal pole.
