Transcript Mitosis Meiosis +

Mitosis
+
Meiosis
Mitosis


One cell divides to make two genetically
identical (diploid) cells
Five stages:



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Interphase
Prophase
Metaphase
Anaphase
Telophase
Mnemonics:
 I.P. MAT
 upside-down TAMPI
Interphase

“Resting” period between cell divisions
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Chromosomes replicate
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Centrioles lie outside the nucleus, next to each other
Prophase
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Chromosomes condense
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Each chromosome is two identical chromatids
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Spindles begin to form from the centrioles
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Nuclear envelope fragments and disperses
Late Prophase
(also known as Prometaphase)
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Centrioles move to opposite ends of the cell
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Spindle fibers from both centrioles attach to
each chromosome
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Each centriole is attached to 46 chromosones
Metaphase
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Chromosomes line up on metaphase plate
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Fibers begin to tug each chromosome toward
opposite ends of the cell
Anaphase
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Fibers pull chromatids toward opposite
ends of the cell
Telophase
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Chromatids (now considered chromosomes)
arrive at opposite ends of the cell
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New nuclear membranes form
Cytokinesis
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Movement (kinesis) of the cytoplasm (cyto)
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Rest of the cell divides
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Two genetically identical cells formed
Meiosis


One cell divides to make four genetically
different haploid cells
Ten stages:
Interphase I
 Prophase I
 Metaphase I
 Anaphase I
 Telophase I
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Interphase II
 Prophase II
 Metaphase II
 Anaphase II
 Telophase II
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Interphase I

Same as Mitosis

Chromosomes replicate

Centrioles lie outside the
nucleus
Prophase I

Same as in Mitosis, except
chromosomes attach to
nucleus in homologous pairs
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“Crossing over” occurs
“Crossing Over”
(not that show with John Edward)
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Homologous pairs
exchange sections of
DNA
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This can cause
alleles to be
separated
Late Prophase I
(also known as Prometaphase I)

Same as Mitosis, except
spindle fibers from each
centriole attach to one
chromosome of a
homologous pair
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Each centriole is attached
to 23 chromosones
Metaphase I

Same as Mitosis, except
homologous pairs line up on
either side of the metaphase
plate
Anaphase I
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Homologous pairs separate
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Chromatids do not separate
Telophase I
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Chromosones move towards
the ends of the cell
New nuclear membranes form
Cytokinesis I

Same as Mitosis
Interphase II

Unlike in Mitosis,
Chromosones do not
replicate

(already replicated)
Prophase II

Chromosomes condense

Spindles form and
separate

Nuclear membrane
fragments and disperses

No crossing over
Late Prophase II
(also known as Prometaphase II)

Centrioles move to
opposite ends of the cell

Both sides attach spindle
fibers to chromosones
Metaphase II

Chromosomes align
along the metaphase
plate

Chromosones split into
chromatids and pulled
to both ends
Anaphase II

Fibers pull chromatids
apart and towards
opposite ends of the
cells
Telophase II

Chromatids arrive at
either end of each cell
and new nuclear
membranes form
Cytokinesis II


Rest of the cells divide
Four genetically different
cells formed
Images taken from:
http://www.pbs.org/wgbh/nova/miracle/divi_text.html
http://www.accessexcellence.org/RC/VL/GG/crossing.php
http://www.johnedwardaustralia.com/pictures.htm