After completing this unit, you should be able to: Describe the structural organization of the prokaryotic genome and the eukaryotic genome; list the phases of the cell cycle; describe the sequence of events during each phase; list the phases of mitosis and describe the events characteristic of each phase;. | Chapter 12 The Cell Cycle Overview: The Key Roles of Cell Division The continuity of life Is based upon the reproduction of cells, or cell division Figure Unicellular organisms Reproduce by cell division 100 µm (a) Reproduction. An amoeba, a single-celled eukaryote, is dividing into two cells. Each new cell will be an individual organism (LM). Figure A Multicellular organisms depend on cell division for Development from a fertilized cell Growth Repair 20 µm 200 µm (b) Growth and development. This micrograph shows a sand dollar embryo shortly after the fertilized egg divided, forming two cells (LM). (c) Tissue renewal. These dividing bone marrow cells (arrow) will give rise to new blood cells (LM). Figure B, C The cell division process Is an integral part of the cell cycle Concept : Cell division results in genetically identical daughter cells Cells duplicate their genetic material Before they divide, ensuring that each daughter cell receives an exact copy of the genetic material, DNA Cellular Organization of the Genetic Material A cell’s endowment of DNA, its genetic information Is called its genome The DNA molecules in a cell Are packaged into chromosomes 50 µm Figure Eukaryotic chromosomes Consist of chromatin, a complex of DNA and protein that condenses during cell division In animals Somatic cells have two sets of chromosomes Gametes have one set of chromosomes Distribution of Chromosomes During Cell Division In preparation for cell division DNA is replicated and the chromosomes condense Each duplicated chromosome Has two sister chromatids, which separate during cell division µm Chromosome duplication (including DNA synthesis) Centromere Separation of sister chromatids Sister chromatids Centromeres Sister chromatids A eukaryotic cell has multiple chromosomes, one of which is represented here. Before duplication, each chromosome has a single DNA molecule. Once duplicated, a chromosome consists of two sister . | Chapter 12 The Cell Cycle Overview: The Key Roles of Cell Division The continuity of life Is based upon the reproduction of cells, or cell division Figure Unicellular organisms Reproduce by cell division 100 µm (a) Reproduction. An amoeba, a single-celled eukaryote, is dividing into two cells. Each new cell will be an individual organism (LM). Figure A Multicellular organisms depend on cell division for Development from a fertilized cell Growth Repair 20 µm 200 µm (b) Growth and development. This micrograph shows a sand dollar embryo shortly after the fertilized egg divided, forming two cells (LM). (c) Tissue renewal. These dividing bone marrow cells (arrow) will give rise to new blood cells (LM). Figure B, C The cell division process Is an integral part of the cell cycle Concept : Cell division results in genetically identical daughter cells Cells duplicate their genetic material Before they divide, ensuring that each daughter cell receives an .
