The Cell Cycle
¿ 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
1. Interphase
2. Mitosis
(Nuclear
division)
3. Cytokinesis
(Division
of
cytoplasm) ?s 1-6
Interphase
1.
2.
3.
G1 (Gap 1)
S (Synthesis)
G2 (Gap 2)
Interphase
G1
- rapid cell growth
- basic cell f(x)s*
* f(x) = function
Interphase
S=
Synthesis
– DNA replication
Interphase
G2 =
Organelles
made
G1
S
G2
Cell during Interphase :
“ DNA
in form
of chromatin
DNA looks like
hair /
spaghetti
(chrs.
not visible)
The Cell Cycle
?s 7-12