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The Cell Cycle & Cell Division
The Cell Cycle

Most cells in an organism
go through a cycle of
growth, development,
and division called the
cell cycle.

The cell cycle allows
organisms :



to grow and develop
replace old or damaged
cells
produce new cells.
Phases Of The Cell Cycle
There are two main phases of the cell cycle:
1. Interphase
2. Mitotic phase
Interphase
Interphase is a period of
growth and development
for a cell.
It makes up most of the
cell cycle
 During interphase, The
DNA of the cell is
called chromatin

Interphase
During interphase, cells go through three stages:
1. Rapid growth and
replication of the
organelles. (G1 stage)
Interphase
2. Replication of DNA . (S stage)
 The cell replicates its strands
of chromatin
 Sister chromatids are the
two identical strands of
DNA that make up the
duplicated chromosome.
 They are held together
by a structure called a
centromere.
Interphase
3. Growth and final preparation for cell division (G2 Stage
Mitotic Phase
Mitosis- The process of cell division that
results in 2 identical cells(daughter cells)
with the same number of chromosomes.


Only happens in body cells
Sub-stages of Mitosis:
Prophase
 Metaphase
 Anaphase
 Telophase


Cytokinesis
Prophase

Duplicated DNA condenses into chromosomes
Metaphase

Chromosomes line up in the middle of the cell
Anaphase

Sister chromatids in each duplicated chromosome
separate and are pulled in opposite directions by the
spindle fibers
Telophase

Chromosomes begin to uncoil, and 2 new identical
nuclei form
Cytokinesis

Cytokinesis divides a cell’s cytoplasm forming a
new cell membrane around each daughter cell.

In animal cells , a furrow in the middle of the cell
gets deeper until the cell membrane comes
together to divide the cell.
Cytokinesis

In plants, a cell plate grows outward toward a new
cell wall until 2 new cells form
The cell cycle is important for :
 for reproduction in some organisms
 growth in multi-cellular organisms
 replacement of worn-out or damaged cells
 Repair of damaged tissues