Transcript Mitosis - Beacon Media

Mitosis
 Mitosis enables organisms to grow, repair and replace
damaged or lost parts.
 The process of mitosis produces two new cells from
one.
 These new cells have identical chromosome sets to the
parent cell.
 Mitosis is a continuous process once begun, but for
reference we divide the process into several stages.
Interphase
During interphase the cell is
functioning normally.
Inside the nucleus the chromosomes
are present as indistinguishable
threads known as chromatin.
Centrioles are present.
Prophase
Chromatin in the nucleus begins to condense and becomes visible
under the light microscope as chromosomes.
The nuclear membrane disappears. Centrioles begin moving to
opposite ends of the cell and fibres extend from the centromeres.
Some fibres start to cross the cell to form the mitotic spindle.
Metaphase
Spindle fibres align the chromosomes along the middle of the cell
nucleus, attached to the centromere. This line is referred to as the
metaphase plate or equator.
This organization helps to ensure that in the next phase, when the
chromosomes are separated, each new nucleus will receive one
copy of each chromosome.
Anaphase
The paired chromosomes separate at the centromere and
move along the spindle fibre to opposite poles of the cell.
Telophase and Cytokinesis
Chromatids arrive at opposite poles
of cell, and new nuclear
membranes form around the
daughter nuclei.
The chromosomes lengthen and
are no longer visible under the
light microscope. The spindle fibres disperse, and cytokinesis or
the partitioning of the cell may also begin during this stage.
The cell cycle
In animal cells, cytokinesis results when a fibre ring composed
of a protein around the centre of the cell contracts
pinching the cell into two daughter cells, each with one nucleus.
In plant cells, the rigid wall requires that a cell plate be
synthesized between the two daughter cells.
Click on the links below to view animations:
http://www.biology.arizona.edu/cell_bio/tutorials/cell_cycle/M
itosisFlash.html http://iknow.net/cell_div_education.html
Can you label each of the stage of Mitosis
and place them in correct order?
b
c
e
a
d
References
 http://www.ias.unt.edu/~tpp001/Mitosis_Diagram_Page.main.html
 http://www.biology.arizona.edu/cell_bio/tutorials/cell_cycle/cells3.html
 http://www.biology.arizona.edu/cell_bio/tutorials/cell_cycle/MitosisFlash
.html
 http://iknow.net/cell_div_education.html
Collated by Debbie Alam
2012