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Mitosis
ReviewWhat is the cell cycle?What are the two stages of the cell cycle?
Why do cells need to divide?
ChromosomesIn cells DNA is tightly wound up into chromosomes
Chromosomes are not visible, but become visible in mitosis
Humans have 23 pairs of chromosomes
Chromosome before DNA replication
Chromosome after DNA replication
Chromatid – One half of a duplicated chromosome
Centromere – Middle of a chromosome
Midlesson ReviewWhat is a chromosome?How many pairs of chromosomes do humans have?
What is a centromere?
Mitosis4 stages
ProphaseMetaphaseAnaphaseTelophase
Prophase1st stageNuclear envelope breaks down
Chromosomes become visible
Spindle forms
MetaphaseChromosomes line up in middle
Spindle attaches to each centromere
AnaphaseEach sister chromatid is pulled apart
TelophaseThe two sets of chromosomes are now at separate ends of the cell
Two nuclear envelopes form around the chromosomes
Cytokinesis –Not Mitosis--After mitosis the cell splits in two
Animals – cell pinches down the middle
Plants – Cell plate forms down the middle
ReviewWhat are the 4 phases of mitosis?What happens in first stage of
mitosis?What happens in the second stage of
mitosis?What happens in the third stage of
mitosis?What happens in the fourth stage of
mitosis?What happens in cytokinesis?