Download Cells divide during the mitotic phase

Cells divide during the
mitotic phase
Section 9.3
Parts of the Mitotic Phase
Introduction to Mitosis
Interphase
Cell prepares for division
by:
•replicating DNA and
organelles
•increasing cell size
Interphase Cont.



G1 (Gap) Phase:
* Growth-the cell grows in size.
S (Synthesis) Phase of Cell Cycle:
* The cell duplicates its chromosomes and cellular
contents.
* The chromosomes are in the form of chromatin
(long and stringy material)
G2 (Gap) Phase of the Cell Cycle:
* The cell prepares the enzymes and machinery for
mitosis.
Stages of Mitosis
Prophase

Cell prepares for nuclear division
by:

condensing DNA into movable
packages called chromosomes

DNA wrapped around histone
proteins
Early Prophase
Late Prophase
Prophase Cont.
Early Prophase
 During early prophase, the
chromosomes condense,
making them
distinguishable when using
a light microscope.
 The nuclear envelope
disperses.
Late Prophase
 During late prophase, the
nucleoli disappear and the
mitotic spindle apparatus
assembles.
 The mitotic spindle will
consist of microtubules
that extend from pole to
pole.
Metaphase

Cell prepares
chromosomes for division
by:


aligning chromosomes at
cell equator
attaching spindle fibers
from each new daughter
cell pole to each
chromosome at the
centromere
Anaphase

Chromosomes divide:


spindle fibers pull
chromosomes apart
one-half of each
chromosome (chromatid)
moves to a new daughter
cell
Early Anaphase
Late Anaphase
Telophase

Cytoplasm divides:



DNA decondenses and two
nuclei form
new cell wall (cell plate)
appears between the two
nuclei to form two new
daughter cells
The process of cytokinesis,
where the cytoplasm is
divided by cleavage, also starts
sometime in late anaphase and
continues through telophase
Daughter Cells

The final steps are :

completion of the total
formation of a membrane
between each of the new
daughter cells to yield two
identical but separate new
cells.
Significance of Mitosis

Mitosis results in exactly identical chromosomes in each
daughter cell.

The number of chromosomes stays the same following
mitosis:


a diploid cell produces diploid cells
a haploid cell produces haploid cells
Mitosis Quiz
Concept Check 9.3
1.
Describe a significant event that occurs in each of the
four stages of mitosis.
2.
Compare and contrast cytokinesis in animal and plant
cells.
3.
In what sense may prophase and telophase in mitosis be
characterized as opposites?
Lets See the Whole Process
Lets see Real Cells Divide

http://iknow.net/cell_div_education.html