If I started like that, how
did I get to this?
CELL CYCLE
• Over time, organisms grow; many cells die and need to be replaced.
• The process in a cell’s life cycle when it reproduces to create two new
identical cells is called mitosis.
Cells formed during mitosis are
known as daughter cells.
The stages that a cell goes through during its existence is called the
“cell cycle”
Cell Cycle
• The cell cycle consists of four stages
– G1 (Gap/Growth 1 Phase)
– S (Synthesis Phase)
– G2 (Gap/Growth 2 Phase)
– M (Mitosis/Mitotic Phase)
• The first three phases (G1, S, G2) as a group, are
called Interphase. Cells spend the majority of their
life in this stage.
Interphase – G1
• ‘Gap/Growth' phase in which the cell grows and duplicates internal
organelles (not DNA).
Interphase - S
• Phase when new DNA is synthesized through DNA replication.
Interphase – G2
• ‘Gap/Growth' phase in which the cell grows and checks copied DNA
for any errors.
Mitosis
• Mitosis - M is the phase in which the cell physically divides into two
daughter cells.
Mitosis
• Mitosis has four sub-phases:
– Prophase
– Metaphase
– Anaphase
– Telophase
PROPHASE
• Chromatin (DNA) condenses, the nuclear membrane breaks down, and
spindle fibers form from centrioles.
METAPHASE
• Replicated chromosomes line up in the middle of the cell.
• Spindle fibers attach to the centromere of each chromosome.
ANAPHASE
• Chromosomes begin to be pulled apart, and the cell becomes elongated,
with distinct ends (poles).
TELOPHASE
• Nuclear membrane re-forms around the separated chromosomes
• Chromosomes begin to uncoil.
CYTOKINESIS
The final division of the cytoplasm that completes the process of mitosis
making two complete, identical daughter cells.
• ANIMAL CELLS
– Cell membrane pinches in to create the cleavage
furrow, separating the cell into two daughter cells,
each with one nucleus.
• PLANT CELLS
– Cell plate forms down center of the cell between the
two nuclei and creates a new cell wall
I Peed on the
MAT…see!
I P M A T C
Basic Mitosis
3D Animated Mitosis
Regulating the Cell Cycle
Proteins called cyclins regulate the timing of the cell cycle.
– These proteins “tell” the cell when it is time to divide.
Cancer - disorder when cells lose the ability to control their growth and
form clusters of irregular cells called tumors.
Cancer & The Cell Cycle
Normal vs. Cancer Cell Growth
METAPHASE
CYTOKINESIS
PROPHASE
ANAPHASE