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Cell Growth and Division
The Cell Cycle & Mitosis
¿ Are cells always dividing?
Sometimes
they are growing
Sometimes
they are preparing
to divide
Sometimes
they are dividing
Cell Division = Mitosis

During life, we go
from one cell to ~
75 trillion cells.
 Mitosis = division
of body cells
 Cancer =
uncontrolled cell
division
Cells that rarely divide
 Mature
skeletal muscle cells
 Nerve cells
Cells that constantly divide


Skin cells
Cells that line gastro-intestinal tract
Cell cycle
=
Period of time between
one cell division & the next
Cell cycle – Phases
I. Interphase
G1 - rapid cell
growth
- basic
cell f(x)s
I. Interphase
S = Synthesis
– DNA
replication
G2 =
Organelles
&
cytosol made
G1
S
G2
Cell cycle - Phases
II. Mitosis = cell division
III. Cytokinesis = cytoplasm
division
?s 1-7
Sequence of Cell Cycle
Interphase
Prophase
Metaphase
Anaphase
Telophase
Mitosis Includes :
Prophase
Metaphase
Anaphase
Telophase
Cytokinesis
(division of cytoplasm)
Cell during Interphase :

DNA in form of
chromatin

Looks like
hair / spaghetti
(chrs. *
not visible)
* chromosomes
Prophase

Chrs. coil and
become visible
 Sister chromatids
move towards
poles
 Spindle forms
 Nuclear envelope &
nucleoli disappear
Metaphase
 Sister
chromatids
line up at equator
on
metaphase plate
(Meet me
in the middle)
Anaphase
 Centromeres
divide, chromatids split
 Sister chromatids move to opposite
poles (centrioles)
(Run away, run away!)
Telophase
 Chrs.
uncoil and become invisible (now
in form of chromatin)
 Spindle disappears
 Nuclear envelope & nucleoli re-appear
Cytokinesis
 Division
into two
identical
DAUGHTER
CELLS
 Starts during
Telophase
 Finishes after
Telophase is over
animation
Whitefish cells during mitosis
?s 8-15