Mitosis Meiosis +
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Transcript Mitosis Meiosis +
Mitosis
+
Meiosis
Mitosis
One cell divides to make two genetically
identical (diploid) cells
Five stages:
Interphase
Prophase
Metaphase
Anaphase
Telophase
Mnemonics:
I.P. MAT
upside-down TAMPI
Interphase
“Resting” period between cell divisions
Chromosomes replicate
Centrioles lie outside the nucleus, next to each other
Prophase
Chromosomes condense
Each chromosome is two identical chromatids
Spindles begin to form from the centrioles
Nuclear envelope fragments and disperses
Late Prophase
(also known as Prometaphase)
Centrioles move to opposite ends of the cell
Spindle fibers from both centrioles attach to
each chromosome
Each centriole is attached to 46 chromosones
Metaphase
Chromosomes line up on metaphase plate
Fibers begin to tug each chromosome toward
opposite ends of the cell
Anaphase
Fibers pull chromatids toward opposite
ends of the cell
Telophase
Chromatids (now considered chromosomes)
arrive at opposite ends of the cell
New nuclear membranes form
Cytokinesis
Movement (kinesis) of the cytoplasm (cyto)
Rest of the cell divides
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
Interphase II
Prophase II
Metaphase II
Anaphase II
Telophase II
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
“Crossing over” occurs
“Crossing Over”
(not that show with John Edward)
Homologous pairs
exchange sections of
DNA
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
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
Homologous pairs separate
Chromatids do not separate
Telophase I
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