THE CELL CYCLE
and
MITOSIS
The Cell Cycle is
divided into 5 phases.
Each phase is
characterized by
specific events which
make the phases easy to
•Mitosis is the division
of the nucleus.
•Mitosis is followed by
cytokinesis or division
of the cytoplasm.
This division produces
two identical daughter
cells. Each daughter
cell has an exact copy
of the chromosomes
from the parent cell.
1. INTERPHASE
Interphase is the busiest
time in the division
process. It is actually
the time between
divisions.
The major event in
interphase is “THE
CELL MAKES
COPIES OF ALL ITS
CHROMOSOMES.”
2. PROPHASE
Prophase is the longest
phase of mitosis.
.
•The nuclear membrane
and nucleolus
disappear.
•During prophase The
centrioles begin to
move apart.
• The chromatin coils
into visible
chromosomes.
Each duplicated
chromosomes is made
of two halves called
sister chromatids.
Each chromosome
consists of two
chromatids attached by
a structure called the
centromere.
•Also during prophase
a system of
microtubules called
the spindle fibers
begin to form between
the centrioles.
3. METAPHASE
•During metaphase the
chromosomes attach to
the spindle fibers and
line up in the middle of
the cell
4. ANAPHASE
•The centromeres split
apart and the chromatid
pairs separate. They
are then pulled toward
opposite ends of the
5. TELOPHASE
•MANY OF THE
CHANGES THAT
TOOK PLACE IN
PROPHASE BEGIN
TO REVERSE.
•The chromosomes
uncoil, the spindle
disappears, and a new
nuclear membrane
forms around each
group of chromosomes
•The cytoplasm begins
to divide, with a
groove forming around
the middle of the cell.
• Finally the cytoplasm
divides (cytokinesis)
forming two new cells
identical to the original
parent cell
Images from the
University of Arizona
Biology Project
http://www.biology.arizona.edu/
cell_bio/cell_bio. html