The Cell
Cycle
5A
How eukaryotic
cells divide to
make new cells
Just like people have
phases of development,
Cells have phases too.
In somatic (body) cells, a parent
cell produces 2 daughter cells.
The purpose of mitosis is for
growth and repair of tissue.
Three Phases or Stages
1. Interphase
2. M (Mitosis) phase
3.Cytokinesis
Interphase
Interphase
 DNA and organelles
replicate
 Cell spends most of its life in
this stage
Stages of Interphase
G1 (growth)
S (synthesis)
G2 (growth)
G1 (growth)
• Aka First Gap
• The cell grow larger
• Makes proteins and
organelles
S (synthesis)
• DNA replication occurs - genetic
material is duplicated so each
daughter cell contains the same
amount of genetic material as the
parent cell
• Chromosomes duplicate to form
sister chromatids
G2 (growth)
• Aka Second Gap
• More growth & protein
synthesis occurs
• preparing for cell division
M phase
• Aka Mitosis
• Shortest of all phases
• Division of the
nucleus
Mitosis
Nucleus divides
 Duplicated DNA is divided
into two new nuclei

Mitosis Animation
Stages of Mitosis
Prophase
Metaphase
Anaphase
Telophase
Prophase
Prophase
• Nuclear membrane breaks down
• Genetic material (chromosomes)
enlarges, thickens &condenses
• In the cytoplasm, Centrioles
migrate to opposite ends of poles
• Microtubules attach to centrioles
Prophase
Metaphase
Metaphase
• Duplicated chromosomes line
up on the equator of the cell
• Spindles attach to
chromosomes at the
centromere & pull the sister
chromatids into a line in the
center of the cell
Metaphase
Anaphase
Anaphase
• Shortest phase
• As the spindle contracts,
the sister chromatids
separate and are pulled
to opposite sides of the
cell
Anaphase
Telophase
Telophase
• New nuclear membranes
form to separate the
genetic material
• Chromosomes shrink
• Spindle breaks apart
Telophase
Mitosis
Cytokinesis
Cytokinesis
• Occurs AFTER telophase
and BEFORE interphase
• Cytoplasm divides
• Forms 2 new cells
Cytokinesis
http://outreach.mcb.harvard.edu/animations/
cellcycle.swf
Identify the stage of the cell cycle…
Identify the stage of the cell cycle…
Identify the stage of the cell cycle…
Identify the stage of the cell cycle…
http://bio.rutgers.edu/~gb101/lab2_mitosis/in
dex2.html
What happens when cells divide
at an uncontrollable rate?
CANCER
5D
Cancer Animation
Cancer is caused by the loss of cell’s
ability to control division. Cancer
cells divide uncontrollably.
Causes of Cancer
• Tobacco
• Radiation exposure
• Viral infections (HPV)
• Genetics
http://www.mhhe.com/biosci/genbio/virtual_l
abs/BL_23/BL_23.html