The Cell CycleThe Cell Cycle
Cell Division is MitosisCell Division is Mitosis
• For single celled For single celled organisms, this organisms, this increases their increases their population.population.
• For multi-celled For multi-celled organisms, this is organisms, this is for growth, repair, for growth, repair, & differentiation.& differentiation.
Basic StepsBasic Steps
• Duplicate DNADuplicate DNA• Divide Divide
chromosome into chromosome into 2 complete sets.2 complete sets.
• Divide into 2 Divide into 2 identical daughter identical daughter cellscells
Stages of the Cell CycleStages of the Cell Cycle
• InterphaseInterphase• MitosisMitosis
– ProphaseProphase– MetaphaseMetaphase– AnaphaseAnaphase– TelophaseTelophase– CytokinesisCytokinesis
InterphaseInterphase
• 90% of the time 90% of the time the cell is in this the cell is in this phase.phase.
• Preparing for Preparing for division.division.– Copies organelles Copies organelles
7 centrioles7 centrioles
Prophase – Prophase – the start of mitosisthe start of mitosis
• Chromosomes Chromosomes condense.condense.
• Centrioles move to Centrioles move to opposite sides.opposite sides.
• Spindle fibers form.Spindle fibers form.• Nuclear membrane Nuclear membrane
gone.gone.• The chromosome & The chromosome &
their copy are called their copy are called sister chromatids.sister chromatids.
MetaphaseMetaphase
• Sister chromatids Sister chromatids are aligned at the are aligned at the center of cell (the center of cell (the equator).equator).
AnaphaseAnaphase
• Sister chromatids Sister chromatids move towards move towards each side.each side.
• Once separated, Once separated, the chromatids the chromatids are now are now chromosomes chromosomes again.again.
TelophaseTelophase
• Chromosomes are Chromosomes are at each side & at each side & become become chromatin again.chromatin again.
• Spindle fibers Spindle fibers dissolve.dissolve.
• Nuclear Nuclear membrane membrane reforms at each reforms at each side.side.
Cytokinesis in Animal CellsCytokinesis in Animal Cells
• Cytoplasm and Cytoplasm and organelles are organelles are divided equally.divided equally.
• Animal cells have Animal cells have the cell the cell membrane pinch membrane pinch inward to divide inward to divide cell.cell.
• 2 identical 2 identical daughter cells.daughter cells.
Cytokinesis in Plant CellsCytokinesis in Plant Cells
• Cytoplasm and Cytoplasm and organelles are organelles are divided equally.divided equally.
• Cell plate forms in Cell plate forms in the middle and the middle and becomes the cell becomes the cell membrane.membrane.
• Cell wall forms Cell wall forms between the between the membranes.membranes.
Binary FissionBinary Fission
• Prokaryotic cells Prokaryotic cells use this method.use this method.– Bacteria.Bacteria.
• A simple, fast A simple, fast split.split.
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