All About Cell Division Mitosis Presentation Observe Onion Mitosis Mitosis Paper Plate Activity.
5 Mitosis
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Transcript of 5 Mitosis
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Cell cycle
Two main periods
Mitotic phase is a relatively short action-packed period.Interphase
Much longer period, where the cell prepares itself for division.The cell grows by producing proteins andcytoplasmic organelles
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Homologous Chromosomes
Sister Chromatids
Chromosome Replication
When a chromosome divides into identicalchromosomes, the chromatids remainattached at their centromere.
DNA unzips and is duplicated
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Interphase
Stage between cell divisionsDivided into three phases
G1 (first gap) - a cell growsS (synthesis) - continues to grow as someDNA is replicated
The chromosomes begin to replicateG2 (second gap) - grows more and preparesfor mitosis
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Mitotic Phase
MitosisProcess by which a cell separates its
duplicated genome into two identical halves.Cytokinesis
Divides the cytoplasm and cell membraneResults in two identical daughter cells with aroughly equal distribution of organelles andother cellular components.
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Mitosis - 5 subphases
ProphasePrometaphase
MetaphaseAnaphaseTelophase
Impossible to discern an exact "start" and "stop"of the phases.
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Prophase
ChromatinSmall granular particles in the nucleus beginsto condenseBecome visible in the light microscope aschromosomes.
The nucleolus disappears.
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Prophase
CentrioleCytoplasmic organelle – divides into two
Begin moving to opposite ends of the cellFibers extend from the centromeres.
Spindle fibersLong protein moleculesForm a three dimensional arch across the cellbetween the two bodies
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Prometaphase
The nuclear membrane dissolvesProteins attach to the centromeres
creating the kinetochores.links the chromatids to microtubule polymersfrom the mitotic spindle
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PrometaphaseChromosome number is temporarily double –tetraploid
Chromatids become thicker
Can identify lengths and location of centromeresKinetochores of each chromatid move to thespindles equator
MetaphasePro metaphase
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Metaphase
Spindle fibers align the chromosomes
along the middle of the cell – metaphaseplate.Necessary to ensure when the chromatids
are separated, each new nucleus willreceive one copy of each chromosome
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Anaphase
The paired chromatids separate at thekinetochores and move to opposite sidesof the cell.
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Anaphase
Even alignment is due to thecounterbalance of the pulling powersgenerated by the opposing kinetochores,analogous to a tug-of-war between equallystrong people
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Telophase
The chromosomes disperse and are nolonger visible under the light microscope.The spindle fibers disperse.
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Cytokinesis
A fiber ring composed of actin (protein) isformed around the center of the cell
Contracts pinching the cell into twodaughter cells, each with one nucleus.
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Review
Each daughter cell has a complete copy of the genome of its parent cell.
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Interphase
Review