{"id":2388,"date":"2016-05-24T20:37:58","date_gmt":"2016-05-24T20:37:58","guid":{"rendered":"https:\/\/courses.lumenlearning.com\/biologyxwaymakerxmaster\/?post_type=chapter&p=2388"},"modified":"2017-08-01T23:35:21","modified_gmt":"2017-08-01T23:35:21","slug":"reading-mitosis","status":"publish","type":"chapter","link":"https:\/\/courses.lumenlearning.com\/hccs-waymakerbiology1\/chapter\/reading-mitosis\/","title":{"raw":"Mitosis","rendered":"Mitosis"},"content":{"raw":"
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Learning Outcomes<\/h3>\r\nIdentify the characteristics and stages of mitosis\r\n\r\n<\/div>\r\nThe mitotic phase (also known as M phase) is a multistep process during which the duplicated chromosomes are aligned, separated, and move into two new, identical daughter cells. The first portion of the mitotic phase is called\u00a0karyokinesis<\/strong>, or nuclear division. The second portion of the mitotic phase, called cytokinesis, is the physical separation of the cytoplasmic components into the two daughter cells.\r\n

Karyokinesis (Mitosis)<\/h2>\r\nKaryokinesis, also known as mitosis, is divided into a series of phases\u2014prophase, metaphase, anaphase, and telophase\u2014that result in the division of the cell (Figure\u00a01).\r\n\r\n[caption id=\"attachment_3975\" align=\"aligncenter\" width=\"1024\"]\"The Figure 1. Stages of mitosis[\/caption]\r\n\r\nDuring\u00a0prophase<\/strong>, the \u201cfirst phase,\u201d the nuclear envelope starts to dissociate into small vesicles, and the membranous organelles fragment and disperse toward the periphery of the cell. The nucleolus disappears . The centrosomes begin to move to opposite poles of the cell. Microtubules that will form the mitotic spindle extend between the centrosomes, pushing them farther apart as the microtubule fibers lengthen. The sister chromatids begin to coil more tightly and become visible under a light microscope. \u00a0Each sister chromatid develops a protein structure called a kinetochore in the centromeric region (Figure\u00a02). The proteins of the kinetochore attract and bind mitotic spindle microtubules.\r\n\r\n\r\n\r\n
Once a mitotic fiber attaches to a chromosome, the chromosome will be\r\noriented until the kinetochores of sister chromatids face the opposite poles.\r\nEventually, all the sister chromatids will be attached via their kinetochores to microtubules from opposing poles.<\/td>\r\n\"This<\/td>\r\n<\/tr>\r\n<\/tbody>\r\n<\/table>\r\nDuring\u00a0metaphase<\/strong>, all the chromosomes are aligned in a plane called the metaphase plate<\/strong>, or the equatorial plane, midway between the two poles of the cell.\u00a0 At this time, the chromosomes are maximally condensed.\r\n\r\nDuring\u00a0anaphase<\/strong>, the sister chromatids separate at the centromere. Each chromatid, now called a chromosome, is pulled rapidly toward the centrosome to which its microtubule is attached. The cell becomes visibly elongated (oval shaped) as the polar microtubules slide against each other at the metaphase plate where they overlap.\r\n\r\nDuring\u00a0telophase<\/strong>,\u00a0 the chromosomes reach the opposite poles and begin to decondense (unravel), relaxing into a chromatin configuration.\u00a0 Nuclear envelopes form around the chromosomes, and nucleosomes appear within the nuclear area.\r\n\r\nThe activity below will walk you through mitosis\u2014providing you with the chance to review the different steps of the process\u00a0and how they work together.\r\n\r\n