Transcript Meiosis

Meiosis
http://www.biology.arizona.edu/cell_bio/tutorials/
meiosis/main.html
Interphase
• Same as in mitosis
• Growth and
Replication
• G1 – cell growth
• S – replication of
chromosoms
• G2 – growth and
preparation for cell
division
Chromosomes
Karotype
Prophase I
• Chromosomes thicken and
condense ( become visible)
• Centrioles move to the poles
• Nuclear envelop disappears
• Homologous chromosomes come
together during SYNAPSIS to form
a TETRAD
• Crossing-over occurs
Metaphase I
• Chromosomes move to
the equator as a tetrad
• Spindle fibers attach to
chromosome
Anaphase I
• Spindle fibers shorten
• Homologous
chromosomes separate
and move to the poles
Telophase I / Cytokinesis
• Cell membrane begins to pinch
in
• Nuclear membrane reappears
• The cytoplasm divides
• Formation of cell membrane
• Results in two haploid
daughter cells
Meiosis II
• Proceeds just as mitosis with
the exception of chromosome
replication. THEY DO NOT
REPLICATE AGAIN!!!
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Prophase II
Metaphase II
Anaphase II
Telophase II
Cytokinesis
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