Bio 118-Chapter 11 - Chapter 11 Nucleus-Cell Cycle The nucleus-All eukaryotic have a large nucleus surrounded by a double-membrane unclear

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Chapter 11: Nucleus-Cell Cycle The nucleus: -All eukaryotic have a large nucleus surrounded by a double-membrane unclear envelope. -Chromatin: linear eukaryotic chromosomes. -Nuclear lamina: -anchors chromosome -maintain the overall shape and structure of the nuclei? -made of lamins * ribosome synthesis occur in nucleolus. Heterochromatin: condensed DNA that’s highly compacted and supercoiled. Euchromatin: unwound DNA in long filamenous strand. *The nuclear envelope has 2 membranes: continuous with RER. Rough endoplasmic reticulum. * The nuclear envelope contains thousands of openings called nuclear pores. 1) The pore consists of more than 50 different proteins forming the nuclear pore complex. 2) molecules pass in and out of the nucleus through the nuclear pores. Proteins destined for the nucleus has a 17 amino acid (NLS)-nuclear localization signal and allow them to enter the nucleus. Cell division in animals. -cell division of a parent cell yields two daughter cells. -In cell division: the cell divided into 2, nucleus divided into 2, genetic material (DNA) is divided b/tw the daughter cells. *2 types of Cell division: Meiosis/ Mitosis Meiosis : basis of sexual production Division of genetic material in the nucleus to produce 2 daughter cells with ½ the amount of hereditary material found in the parent cells. -Happen only in the production of Gametes (re productive cells) Mitosis: asexual reproductive. division of genetic material genetically identical to the parent cell involves only in the production of somatic cells (body) - distribute the genetic material to the daughter cells. Chromosome : contain a long double helix of DNA wrapped around protein. Gene : a segment of DNA containing the information for synthesizing a protein on RNA molecules. The Cell Cycle: occurs b/tw Mitotic (M) phase (the phase when cell actually divides) Interphase: non-dividing phase -chromosomes are generally uncollied in Heterchromatin and
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euchromatin. -cells spent most time? Two Key events: 1) replication: of hereditary of material 2) separation: of the copied chromosome into 2 daughter cells. When does chromosome replication occur? -chromosome replication occur only in interphase/ not during M phase -DNA synthesis occurs in the S phase The Gap phase: Interphase: 2 Gap phase, during which no DNA synthesis occur. 1) G1 phase: occur before S phase 2) G2 phase: occur after S pahse and before mitosis. -cell perform all their normal cell functions during G1 phase -many cells in the body stop cell division and stay in G1phase. -During the gap phase, organelles replicate and additional cytoplasm is made.
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This note was uploaded on 05/03/2008 for the course BIOLOGY 118 taught by Professor Sherper during the Spring '08 term at Binghamton University.

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Bio 118-Chapter 11 - Chapter 11 Nucleus-Cell Cycle The nucleus-All eukaryotic have a large nucleus surrounded by a double-membrane unclear

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