LIFE 102 Lecture Notes - Lecture 27: Centrosome, Kinetochore, Metaphase
Document Summary
A radical array of short microtubules that extend from each centrosome. *the two centrosomes move to opposite ends of the cell as spindle microtubules grow out of them. Some spindle microtubules attach to the kinetochores of chromosomes and begin to move the chromosomes. Sister chromatids separate and move along the kinetochore microtubules toward opposite ends of the cell. Microtubules shorten by depolymerizing at their kinetochore ends. From opposite poles overlap and push against each other. Genetically identical daughter nuclei form at opposite ends of the cell. Prokaryotes reproduce by a type of cell division called binary fission. The chromosome replicates and the two daughter chromosomes move apart. *since prokaryotes evolved before eukaryotes, mitosis probably evolved from binary fission. *certain protists exhibit types of cell division that seem intermediate between binary fission and mitosis. The eukaryotic cell cycle is regulated by a molecular control system. *the cell cycle appears to be driven by specific chemical signals present in the cytoplasm.
