Download Unit 6 Notes: Mitosis

(1) Big Ideas:
• Mitosis is used to make more Non-Sex cells.
• 1 identical copy of original cell is made.
– 2n  2n
• Happens in Stages:
– DNA condenses.
– Sister Chromatids Line Up.
– Sister Chromatids Separate.
– End with 2 identical cells!
Let’s Watch A Video…
http://www.youtube.com/watch?v=VlN7K1-9QB0
(2) Copying Genetic Information
• DNA is copied in Nucleus
• n = variable for # of chromosomes
– 2n = Full set of Chromosomes in Somatic
Cell
– n = ½ set of Chromosomes
(3) Mitosis Stages
•
•
•
•
Prophase
Metaphase
Anaphase
Telophase
• Cytokinesis  Not REALLY part of
Mitosis, but necessary!
The Parent Cell
Nucleus
(Before Interphase
of the Cell Cycle)
Un-Condensed
DNA
Cell
Membrane
(4) Prophase
• 1st Stage in Mitosis (“Before” Phase)
• Chromatin condenses into chromosomes.
• Chromosomes visible.
• Nuclear Membrane dissolves.
• Centrioles separate to opposite sides of cell.
– Centrioles connect to Spindle Fibers, which will
move the chromosomes around inside the cell.
Dissolving
Nuclear
Membrane
Centromere
Cell
Membrane
Sister Chromatids
(Replicated DNA)
(5) Metaphase
• Sister Chromatids pair up at Metaphase
Plate by each other’s centromere.
• Say What???
– Sister Chromatids  Matching Segments
of DNA (identical genes and alleles).
– Metaphase Plate  The center of the cell.
– Centromere  The center of a
chromosome.
Pairs of
Sister
Chromatids
Centromere
Cell
Membrane
Metaphase Plate
(6) Anaphase
• Sister Chromatid Pairs Separate.
• Spindle Fibers Separate Them.
• Each side of the cell has 1 copy of the
genetic information!
Yes… I know this looks like a butt…..
Separated Chromosomes
Cell
Membrane
(7) Telophase
• Chromosomes are completely separated.
• Chromosomes uncoil.
• Nuclear Membrane Re-Forms.
Reforming
Nuclear
Membrane
Cell
Membrane
Identical Copies!
(Now that’s redundant.)
The Daughter Cells
(After Mitosis)
(8) Cytokinesis
• Splitting of Cytoplasm.
• Splitting & Closing of Cell Membrane.
• In Plants:
– Cleavage Furrow forms  Cell Wall ReForms There!
– Reform Cell Wall AND cytoplasm AND cell
membrane!
Let’s Watch A Video…
http://www.youtube.com/watch?v=VGV3fv-uZYI&feature=response_watch