The Cell Cycle. Cell Division is Mitosis For single celled organisms, this increases their population.For single celled organisms, this increases their.

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.