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PowerLecture: Chapter 9 How Cells Reproduce
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Henrietta says… “Congratulations, you survived Photosynthesis and Respiration!... Welcome to Chapter 9”
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Fig. 9-2, p.141 Henrietta Lacks
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Fig. 9-1, p.140 Henrietta’s Immortal Cells
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HeLa Cells Line of human cancer cells that can be grown in culture Descendents of tumor cells from a woman named Henrietta Lacks Lacks died at 31, but her cells continue to live and divide in labs around the world
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Division Mechanisms Eukaryotic organisms Mitosis Mitosis Meiosis Meiosis Prokaryotic organisms Prokaryotic fission Prokaryotic fission
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a One chromosome (unduplicated) b One chromosome (duplicated) one chromatid two sister chromatids one chromatid Fig. 9-3a, p.142 Stepped Art Chromosome
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Kinetochore forms at centromere during nuclear division Kinetochore - a docking site for microtubules Fig. 9-3a, p.142 Stepped Art Chromosome
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Organization of Chromosomes (the result of condensation of a chromosome) DNA and proteins arranged as cylindrical fiber DNA Histone A protein “spool” one nucleosome “bead” The smallest unit of a eukaryotic chromosome
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core of histone fiber centromere (constricted region) multiple levels of coiling of DNA and proteins beads on a string DNA double helix nucleosome Fig. 9-4, p.143 Chromosome
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DNA and Chromosomes Eukaryotic Chromosome Structure Eukaryotic Chromosome Structure Chromosome Supercoils Nucleosome DNA double helix Histones Coils
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Chromosome Number total # of chromosome types / cell ….(n) Somatic cells diploid (2n) diploid (2n) Gametes haploid (n) haploid (n)
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Fig. 9-6a, p.145 12345 6789101112 131415161718 19202122 XX (or XY) Maintaining Chromosome Number
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The Cell Cycle G1 S G2 Mitosis telophase anaphase metaphase prophase interphase Figure 9.5 Page 144
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Interphase Interphase Once S begins, the cycle automatically runs through G2 and mitosis The cycle has a built-in molecular brake in G1 Cancer involves a malfunction of the “brakes”
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Mitosis nuclear division: ProphaseMetaphaseAnaphaseTelophase Then Cytoplasmic division
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Fig. 9-15, p.153 cell at interphase nucleus cytoplasm telophase prophase anaphase metaphase
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Stopping the Cycle Some cells normally stop in interphase Neurons in human brain Neurons in human brain Arrested cells do not divide Arrested cells do not divide Adverse conditions can stop cycle Nutrient-deprived amoebas get stuck in interphase Nutrient-deprived amoebas get stuck in interphase
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The Spindle The Spindle 2 sets of microtubules that move chromosomes
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Spindle Apparatus one spindle pole one of the condensed chromosomes spindle equator microtubules organized as a spindle apparatus one spindle pole
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microtubule of bipolar spindle p.145 pole Maintaining Chromosome Number
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a Two of the chromosomes (unduplicated) in a parent cell at interphase b The same two chromosomes, now duplicated, in that cell at interphase, prior to mitosis c Two chromosomes (unduplicated) in the parent cell’s daughter cells, which both start life in interphase Fig. 9-6b, p.145 Maintaining Chromosome Number
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Interphase nuclear envelope pair of centrioles Early Prophase Late Prophase Prometaphase Stepped Art Fig. 9-7a, p.146
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Metaphase AnaphaseTelophase Interphase Stepped Art Fig. 9-7b, p.146
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Cytoplasmic Division occurs at the end of mitosis Two mechanisms Cell plate formation (plants) Cell plate formation (plants) Cleavage (animals) Cleavage (animals)
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A ring of microfilaments in the same plane as the spindle equator contracts, dividing the animal cell Animal Cell Division
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Vesicles containing wall materials cluster at equator. Vesicle membranes fuse. Wall material sandwiched between 2 new membranes that lengthen along cell plate. Plant Cell Division
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Cellulose deposited inside sandwich. These will form 2 cell walls. Others form the middle lamella between walls. A cell plate fuses with parent cell membrane. Plant Cell Division
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Animal Cell Division
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Cell Plate Formation Cell Plate Formation cell wall former spindle equator cell plate vesicles converging Stepped Art Fig. 9-8b, p.148
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ring of microfilaments midway between the two spindle poles, in the same plane as the spindle equator Fig. 9-9, p.149 Cell Division
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Fig. 9-10, p.149 Cell Division
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Mitotic Control Kinases Growth factors Checkpoint genes
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Fig. 9-11a, p.150 Mitotic Control
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Fig. 9-11b, p.150 Mitotic Control
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Tumors uncontrollable division forms an abnormal mass called a tumor. Neoplasms - an abnormal mass of cells
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Fig. 9-12, p.150 Cancer
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benign tumormalignant tumor 1 Cancer cells slip of out their home tissue 3 Cancer cells creep or tumble along inside blood vessels, then leave the bloodstream the same way they got in. They start new tumors in new tissues. 2 The metastasizing cells become attached to the wall of a blood or lymph vessel. They secrete digestive enzymes onto it. Then they cross the wall at the breach. Fig. 9-13, p.151Cancer
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Fig. 9-14a, p.151 Cancer
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Fig. 9-14b, p.151 Cancer
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Fig. 9-14c, p.151 Cancer
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Mitosis lab Onion Root Tip & Whitefish Blastula
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Mitosis lab Onion Root Tip & Whitefish Blastula Determine and display the % of their time spent in Mitosis.
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Mitosis lab Onion Root Tip & Whitefish Blastula Determine and display the % of their time spent in Mitosis. Today - Write Hypothesis and “Methods” section Get approval and turn in.
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Mitosis lab Onion Root Tip & Whitefish Blastula Determine and display the % of their time spent in Mitosis. Today - Write Hypothesis and “Methods” section Get approval and turn in. Wednesday - Do procedure in class
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Mitosis lab Onion Root Tip & Whitefish Blastula Determine and display the % of their time spent in Mitosis. Today - Write Hypothesis and “Methods” section Get approval and turn in. Wednesday - Do procedure in class Friday – Turn in report (1 per group) including Methods, Data, and just your display of the % times as your conclusion
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