Cell Growth & Division
Your Life Story
2
cells to ~75 trillion
 How
much is a trillion?
$100 dollars
Largest bill in
circulation
$10,000 dollars
Less than half an inch
thick
100 $100 bills
$1 million dollars
100 packets of $10,000
$100 million dollars
100 packets of $1 million
$1 billion dollars
10 $100 million pallets
$1 trillion dollars
• There are only 7.2 billion people in the
world
• There are about 100 billion stars in the
galaxy
YOUR BODY = 75 trillion cells
Each cell has
the SAME
copy of DNA
in it
How do we make sure those DNA copies are
right?
What if it goes wrong?
Chromosomes
 Genetic
information (DNA) is bundled into
packages called chromosomes
 Chromatid:
one copy of newly
replicated chromosome
 Joined
to the other chromatid by a
centromere
Why do cells replicate THEMSELVES?
Cells go through mitosis for development, growth, and repair.
The Cell Cycle
 1.
Interphase (preparing)
(80% of time)
Cell Cycle
1. Growth
2. DNA replication, twice as much
Mitosis (division)
Interphase DNA at the end of this phase
(20% of time)
 2.
3. Preparing for cell division
Cell Division
1. Mitosis (cell division)
2. Cytokinesis (Division of
cytoplasm)
The Cell Cycle
4
Phases: G1, S, G2, M
Interphase
Cell Cycle
G1 – Growth
S – “Synthesis” – DNA replication,
twice as much DNA at the end of
this phase
G2 – Preparing for cell division
Cell Division
M – 1. Mitosis (cell division)
- 2. Cytokinesis (Division of
cytoplasm)
The Cell Cycle
Warm Up
 Label
this chromosome!
3.___________
2.___________
1.___________
1. PROPHASE
Chromosomes
condense & coil.
Nuclear membrane
disintegrates.
Spindle fibers form.
2. METAPHASE
Chromosomes
align in center
by their
centromeres
Attach to
spindle
3. ANAPHASE
Chromatids separate.
Chromatids pulled by the
spindle fibers to opposite
ends of the cell
4. TELOPHASE
The cells divide into
two.
The chromosomes
uncoil and the nucleus
reforms.
5. CY TOKINESIS
 Cytoplasm pinches in half
Each daughter cell has an identical set of duplicate
chromosomes
DNA Replication then Mitosis
MITOSIS (Cell Division)
STOP-MOTION MITOSIS
Move objects very slowly and
take several
photos
You can adjust the speed
Make sure the phases are
labelled with paper!