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5.2 Mitosis and Cytokinesis
Cells divide during mitosis
5.2 Mitosis and Cytokinesis
During Mitosis, the DNA is coiled to prevent it from being
tangled. We call the coiled DNA chromosomes. After
mitosis, it uncoils so that it may be used by the cell.
DNA double
helix
DNA and
histones
Chromatin
Supercoiled
DNA
5.2 Mitosis and Cytokinesis
Sister Chromatids
chromatid
• One half of a duplicated
chromosome is a chromatid.
• Duplicate copies are called
Sister chromatids. They are held
together at the centromere.
• Telomeres are at the ends of the
chromosomes. They protect
DNA and do not include genes.
telomere
centromere
telomere
Condensed, duplicated
chromosome
5.2 Mitosis and Cytokinesis
Interphase
Not a phase of Mitosis.
Parent cell
centrioles
• Includes G1, S, G2
• DNA is checked for
mistakes, duplicated, &
checked again.
• Normal cell activity-life!
• Interphase prepares
the cell for Cell division
spindle fibers
nucleus
nucleus with
DNA
centrosome
5.2 Mitosis and Cytokinesis
Prophase—Wind Up!
• Chromosomes condense
• Spindle fibers form, Centrioles move to poles
• Membrane around nucleus begins to dissolve
5.2 Mitosis and Cytokinesis
Metaphase—Line Up!
• chromosomes line up in the middle of the cell
• Spindle Fibers attach to Centromere.
• point are spindle fibers attached???
Spindle fiber
Centriole
Centromere
5.2 Mitosis and Cytokinesis
Anaphase-Separate!
• sister chromatids are pulled apart by the spindle
fibers.
5.2 Mitosis and Cytokinesis
Telophase--Divide
• Nucleus begins to form in each cell
• chromosomes begin to uncoil
5.2 Mitosis and Cytokinesis
Cytokinesis
• Cytoplasm and
organelles are
divided between 2
daughter cells.
• DNA is uncoiled
• In animal cells, the
membrane pinches
closed.
• In plant cells, a cell
plate forms (new cell
wall) between the
cells.