today's biology topic cellular division
Skinny Cartman
http://en.wikipedia.org/wiki/Mitosis
The process of mitosis is complex and highly regulated. The sequence
of events is divided into phases, corresponding to the completion of
one set of activities and the start of the next. These stages are
prophase, prometaphase, metaphase, anaphase and telophase. During the
process of mitosis the pairs of chromosomes condense and attach to
fibers that pull the sister chromatids to opposite sides of the cell.
The cell then divides in cytokinesis, to produce two identical
daughter cells
http://en.wikipedia.org/wiki/Mitosis#Telophase
Telophase (from the Greek τελος meaning "end") is a reversal of
prophase and prometaphase events. It "cleans up" the after effects of
mitosis. At telophase, the nonkinetochore microtubules continue to
lengthen, elongating the cell even more. Corresponding sister
chromosomes attach at opposite ends of the cell. A new nuclear
envelope, using fragments of the parent cell's nuclear membrane, forms
around each set of separated sister chromosomes. Both sets of
chromosomes, now surrounded by new nuclei, unfold back into chromatin.
Mitosis is complete, but cell division is not yet complete.
Skinny Cartman
> http://en.wikipedia.org/wiki/Mitosis
>
> The process of mitosis is complex and highly regulated. The sequence
> of events is divided into phases, corresponding to the completion of
> one set of activities and the start of the next. These stages are
> prophase, prometaphase, metaphase, anaphase and telophase. During the
> process of mitosis the pairs of chromosomes condense and attach to
> fibers that pull the sister chromatids to opposite sides of the cell.
> The cell then divides in cytokinesis, to produce two identical
> daughter cells
>
> http://en.wikipedia.org/wiki/Mitosis#Telophase
>
> prophase and prometaphase events. It "cleans up" the after effects of
> mitosis. At telophase, the nonkinetochore microtubules continue to
> lengthen, elongating the cell even more. Corresponding sister
> chromosomes attach at opposite ends of the cell. A new nuclear
> envelope, using fragments of the parent cell's nuclear membrane, forms
> around each set of separated sister chromosomes. Both sets of
> chromosomes, now surrounded by new nuclei, unfold back into chromatin.
> Mitosis is complete, but cell division is not yet complete.
On a related note
http://en.wikipedia.org/wiki/Meiosis#Meiosis-phases
During prophase I, DNA is exchanged between homologous chromosomes in
a process called homologous recombination. This often results in
chromosomal crossover. The new combinations of DNA created during
crossover are a significant source of genetic variation, and may
result in beneficial new combinations of alleles. The paired and
replicated chromosomes are called bivalents or tetrads, which have two
chromosomes and four chromatids, with one chromosome coming from each
parent. At this stage, non-sister chromatids may cross-over at points
called chiasmata (plural; singular chiasma).
During these stages, two centrosomes, containing a pair of centrioles
in animal cells, migrate to the two poles of the cell. These
centrosomes, which were duplicated during S-phase, function as
microtubule organizing centers nucleating microtubules, which are
essentially cellular ropes and poles. The microtubules invade the
nuclear region after the nuclear envelope disintegrates, attaching to
the chromosomes at the kinetochore. The kinetochore functions as a
motor, pulling the chromosome along the attached microtubule toward
the originating centriole, like a train on a track. There are four
kinetochores on each tetrad, but the pair of kinetochores on each
sister chromatid fuses and functions as a unit during meiosis I. [2]
[3]
Microtubules that attach to the kinetochores are known as kinetochore
microtubules. Other microtubules will interact with microtubules from
the opposite centriole: these are called nonkinetochore microtubules
or polar microtubules. A third type of microtubules, the aster
microtubules, radiates from the centrosome into the cytoplasm or
contacts components of the membrane skeleton.
spintronic
> http://en.wikipedia.org/wiki/Mitosis
>
> The process of mitosis is complex and highly regulated. The sequence
> of events is divided into phases, corresponding to the completion of
> one set of activities and the start of the next. These stages are
> prophase, prometaphase, metaphase, anaphase and telophase. During the
> process of mitosis the pairs of chromosomes condense and attach to
> fibers that pull the sister chromatids to opposite sides of the cell.
> The cell then divides in cytokinesis, to produce two identical
> daughter cells
>
> http://en.wikipedia.org/wiki/Mitosis#Telophase
>
> prophase and prometaphase events. It "cleans up" the after effects of
> mitosis. At telophase, the nonkinetochore microtubules continue to
> lengthen, elongating the cell even more. Corresponding sister
> chromosomes attach at opposite ends of the cell. A new nuclear
> envelope, using fragments of the parent cell's nuclear membrane, forms
> around each set of separated sister chromosomes. Both sets of
> chromosomes, now surrounded by new nuclei, unfold back into chromatin.
> Mitosis is complete, but cell division is not yet complete.
Ya, that really evolved,LMAO.
http://www.youtube.com/watch?v=VlN7K1-9QB0
http://www.youtube.com/watch?v=VGV3fv-uZYI&annotation_id=annotation_706798&feature=iv
Sidenote: