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Chapter 12: Cell Cycle. Cell Division. Reproduction Growth repair. Genome Chromosomes Somatic cells Gametic cells Chromatin (duplicates) Centromere Sister chromatids. Reproduction. Growth and Development. Tissue Renewal. Mitosis vs. Meiosis. Mitosis division of nucleus - PowerPoint PPT Presentation
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Chapter 12: Cell CycleFigure 12.0 Mitosis
Cell DivisionReproductionGrowthrepair
GenomeChromosomesSomatic cellsGametic cellsChromatin (duplicates)CentromereSister chromatids
Figure 12.3 Chromosome duplication and distribution during mitosis
Figure 12.1a The functions of cell division: Reproduction
Figure 12.1b The functions of cell division: Growth and development
Figure 12.1c The functions of cell division: Tissue renewal
Reproduction
Growth and Development
Tissue Renewal
Mitosis vs. Meiosis
Mitosis division of nucleusCytokinesis division of cytoplasm
Meiosis produces gametesMitosis produces clones
The cell cycle
The Cell Cycle (cell growth) Interphase (90%)
G1:cell growthS:copies chromosomesG2:preps for division
Mitotic phase (M)
Figure 12.4 The cell cycle
What’s the purpose of Interphase?
Cell growth, produce proteinsHigh Metabolic ActivityPrepares for divisionSingle centrosomes replicatesCentrosomes move apartSpindle Poles form
Magnificent Mitosis!PPMAT
Prophase Prometaphase metaphase anaphase telophase
Prophase
What happens to the chromatin?What happens to the nucleolus?Sister chromatids, centromereWhat happens to the nuclear
envelope (membrane)?
Prometaphase
Nuclear envelope dissolvesMicrotubules of the spindle
contact chromosomes (kineticore)
Metaphase
“Meet in the Middle”spindle microtubulescentrioles
Anaphase
Sister chromatids separate and move to opposite poles (now called chromosomes) spindle microtubules centrioles
Telophase and Cytokinesis
Reverse of prophase chromatin nucleoli nuclear envelope
Cytokinesis
Figure 12.7 Testing a hypothesis for chromosome migration during anaphase
Cytokinesis :a closer look
Cleavage Furrow Occurs along old metaphase plate
Actin Microfilaments“pulling of drawstrings”Plants form a “cell plate” vesicles
move to middle. Cell plate fuses with plasma
membrane
Figure 12.8 Cytokinesis in animal and plant cells
Molecular ControlRegulation by internal and external
checkpoints G1 in mammals, if stop cell arrests in G0
phase. (nerve cells always in G0)
Cyclin dependent Kinases (Cdks) Cyclins bind to Cdks during G2, forming
MPF complex which initiates mitosisGrowth Factors: PDGFAnchorage Dependent
CheckpointsFigure 12.13 Mechanical analogy for the cell cycle control system
Cell Cycle Clock
Kinase Dependent: enzymes that activate or inactivate other proteins by phosphorylation.
Cyclin: protein kinase must be attached to, for enzyme to be active. Constant Conc. of Enzyme, varying conc. of cyclin
MPFs (maturation promoting factor) first Kinase discovered.
Control LinkCell Cycle Game
CancerCancer cellsBenign tumorMalignant tumor
MetastasisProto-oncogenesOncogenes
Figure 12.15 The effect of a growth factor on cell division