the centrosome is a nonmembranous organelle that organizes the cell�s microtubules

The centrosome is a nonmembranous organelle that organizes the cell�s microtubules

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microtubules between them PrometaphaseThe nuclear envelope fragmentsThe microtubules extend toward the center of the cell as kintochores develop around the centromere, then the microtubules attach to the kinetochores as non kinetochore microtubules interact with those from the opposite pole.MetaphaseLongest stage of mitosis, lasting about 20 minutes centrosomes are now at the opposite ends as the chromosomes line up on the metaphase plate aka the chromosomes line up in the middleAnaphase shortest stage, lasting only a few minutestwo sister chromatids part and each chromatide becomes a chromosome.the chromosomes move twoard opposite ends as the kinetochore microtubules shorten, they move centromere first at 1 mewmeter/min the cell elongates as the nonkinetochore microtubules lengthen Telophase Nucelar envelopes arise from the fragments of the parent cell’s nucelar envelope and other portions of the endomembrane system the chromosomes become less condensed Identical daughter cells are formed Cytokinesis the cleavage furrow forms to pinch the cells in two ( the cleavage furrow is made of protein myosin and actin.Polar microtubules are microtubules that interact with microtubules from the other poleSeparating the chromosomes are made possible by motor proteins that walk the organelle down a microtubule which requires ATPIn plant cells a Cell plate forms late during telophase with vesicles derived from the golgi appartus that coalesce, producing a cell plate.Binary Fissiondivision that prokaryotes undergo in order to reproducemost genes are carried on a single bacterial chromosome that is a circular DNA molecule and associated proteinsbinary fission begins when the Dna of the bacterial chromosome replicates at the origin of replication which produces two origins as one copy of the origin moves to the other end of the cell, as replication continues one copy will be at each end of the cell. When replication finishes the plasma membrane grows inward and the new cell is depositeTheory/hypothetical sequence of the evolution of mitosis goes prokaryotes, dinoflagellates, diatoms, eukaryotesCell Cycle Regulation and Cytoplasmic Signalsthe cell cycle control system, a cyclically operating set of molecules in the cell that both triggers and coordinates key events in the cell cyclethree major checkpoints are found in the G1, G2, and M phases but for many cells the G1 checkpoint is the restriction and maybe the most importanCell cycle clock made up of Cyclins and Cyclin-Dependent KinasesKinases are enzymes that activate or inactiveate other proteins by phosphorylating them, particular kinases
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This note was uploaded on 04/09/2008 for the course BIO 311D taught by Professor Reichler during the Spring '08 term at University of Texas.

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The centrosome is a nonmembranous organelle that organizes the cell�s microtubules

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