1. 5.1 The Cell Cycle
KEY CONCEPT
Cells have distinct phases of growth, reproduction,
and normal functions.
What does it mean for a
cell to be immortal?

2. 5.1 The Cell Cycle
Cells double their DNA in order to divide and create
two nearly identical duplicates or copies.
Divide – to separate
Duplicate – an identical copy
Double – to increase twofold
Copy – a reproduction of an original

3. 5.1 The Cell Cycle
The cell cycle has four main stages.
– Gap 1 (G1): 2. cell growth
and normal functions,
double organelles
– DNA synthesis (S): 4.
copies DNA, Replication
– Gap 2 (G2): 6. additional
growth, normal functions
• The main stages of the cell cycle are

4. 5.1 The Cell Cycle
The cell cycle has four main stages.
• The main stages of the cell cycle
• Take out a textbook and turn to
CH 5.1 – page 134
Copy down the diagram (just
like the one to the right) and
make sure to take detailed notes
on what happens in each part of
the cell cycle!

5. 5.1 The Cell Cycle
Cells divide at different rates.
• The rate of cell division varies with the need for
those types of cells.
• Some cells are unlikely to divide (G0).

6. 5.1 The Cell Cycle
Cell size is limited.
• Volume increases faster than surface area.

7. 5.1 The Cell Cycle
• Surface area must allow for adequate
exchange of materials.
– Too small, not enough machinery
– Too big, nutrients and waste can’t move in/out
– Cell growth is coordinated with division.
– Cells that must be large have unique shapes.

8. 5.1 The Cell Cycle
• Mitosis occurs only if the cell is large enough and the DNA
undamaged.
– Interphase
– Mitosis (M): Cell division
includes division of the cell
nucleus (mitosis) and
division of the cell
cytoplasm (cytokinesis)
– Prophase
– Metaphase
– Anaphase
– Telophase
– cytokinesis

9. 5.1 The Cell Cycle
• What are the four main parts of the cell cycle?
• What phase are cells in during the majority of
their life span?
• Why is surface area to volume ratio important for
cells?
• Why would some cells have a shorter life cycle
than others?
• Are there cells that rarely or never divide?

10. 5.1 The Cell Cycle
• What are the four main parts of the cell cycle?
• What phase are cells in during the majority of
their life span?
• Why is surface area to volume ratio important for
cells?
• Why would some cells have a shorter life cycle
than others?
• Are there cells that rarely or never divide?