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19 Cards in this Set
- Front
- Back
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Four events must occur for cell division:
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• Reproductive Signal: to initiate cell division
• Replication: of DNA • Segregation: distribution of the DNA into the two new cells • Cytokinesis: separation of the two new cells |
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Reproductive Signal
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To initiate cell division
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Replication
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Of DNA
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Segregation
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Distribution of the DNA into the two new cells
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Cytokinesis
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Separation of the two new cells
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Characteristics of binary fission
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External factors such as nutrient concentration and environmental conditions are the reproductive signals initiate cell division.
For many bacteria, abundant food supplies speed up the division cycle. |
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Prokaryote DNA have...
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one chromosome, a single molecule of DNA; usually circular.
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Binary Fission: Prokaryote Cell Division
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The circular DNA replicates,
The cell grows, Daughter DNA’s are segregated, Cytokinesis (cell separation) follows |
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Cytokinesis
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separation of cells during division
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Cell Cycle
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Events that occur
to produce two eukaryotic cells from one. Interphase- when cell is not dividing, End phase- mitosis/meiosis occurring |
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Interphase
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• the period between cell divisions
• There are 3 subphases: 1. G1 : “gap 1” 2. S: “synthesis”- doubling DNA, one chromatid before S phase, then sister chromatids made b/c of replication 3. G1: “gap 2”- cell almost ready |
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M-phase
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When Mitosis/Meiosis and cytokenisis is occurring
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How DNA is “packaged”
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• Double helix in a loose mass during interphase
• DNA wraps itself around histones (8) to make a nucleosome • Chromatin- densely coiled nucleosomes • Gene- Strech of DNA codes for protein • DNA organized into chromosomes • Chromosomes made out of chromatin |
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Histones
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Molecules that DNA wraps itself around during packaging (8 bundled together during wrapping)
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Nucleosome
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DNA wrapped around 8 histones
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Chromatin
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Densely coiled nucleosomes
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Gene
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Stretch of DNA that codes for protein
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Chromosome
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Composed of two chromatids
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Spindles "microtubles"
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Chromosome rail road tracks- physical structures- attach to chromosome at kinetochore to pull chromosomes apart
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