B.How Animal Cells Divide Prophase a.Chromatin condenses and chromosomes become visible. b.Nucleolus disappears and the nuclear envelope fragments. c.Short microtubules radiate out from the pair of centrioles located in each centrosome; form starlike asters.
B.How Animal Cells Divide Prometaphase a.attachment of chromosomes to the spindle and movement as they align at the metaphase plate (equator).
B.How Animal Cells Divide Metaphase a.Chromosomes align at the metaphase plate.
B.How Animal Cells Divide Anaphase a.Two sister chromatids of each duplicated chromosome separate at centromere. b.Daughter chromosomes, each with a centromere and single chromatid, move to opposite poles.
B.How Animal Cells Divide Telophase a.Spindle disappears. b.Chromosomes decondense and return to chromatin; the nuclear envelope reforms and nucleoli reappear. c.Cytokinesis is nearly complete.
Cytokinesis in Animal Cells a.Cleavage furrow indents the plasma membrane between the two daughter nuclei at a midpoint; progressively divides cytoplasm during cell division.
C.How Plant Cells Divide 1.Plant meristematic tissue in tips of roots and shoots 2.Stages are same as in animal cells. 3.Plant cells - no centrioles, and asters do not form.
Cytokinesis in Plant Cells Golgi apparatus produces vesicles that move to the midpoint between the daughter cell nuclei Vesicles fuse, forming a cell plate
How the Cycle is Controlled 1.Some cells divide continuously 2.Other cells are arrested in at different stages
How the Cycle is Controlled 4.Enzymes known as cyclin-dependent kinases (Cdks) regulate passage of cells through these checkpoints
How the Cycle is Controlled Oncogenes (cancer-causing genes) may code for cyclins that no longer function as they should.
Cancer Angiogenesis the formation of new blood vessels. Malignancy and Metastasis ability to move and movment of cancer cells to a new location.
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