Cell Diversity
Clues/Questions
Notes
 Not all cells are alike.
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Even cells within the same organism may show enormous diversity in
size, shape, and internal organization.
For example:
 Your body contains at least 200 different cell types
SIZE
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A few types of cells can be seen without the aid of a microscope (egg
cells, nerve cells in a giraffe – 2m long).
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Most cells are visible only with a microscope.
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Cells are limited in size by the ratio between their outer surface area and
their volume.
This means that if a cell keeps the same shape as it grows, its volume
will increase more rapidly than its surface area
At some point, its surface area becomes too small to allow nutrients,
oxygen, and other materials to enter the cell quickly enough to meet the
cell’s needs (POTATO DEMO)
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SHAPE
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Cells come in a variety of shapes.
This diversity reflects a diversity of functions.
Skin cells are flat (cover the body’s surface).
White blood cells can change shape (leave the blood, enter the areas
surrounding blood vessels, so they can do their job---attack invaders like
bacteria).
INTERNAL ORGANIZATION
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Cells contain a variety of internal structures, called organelles.
Def. a cell component that performs specific functions for the cell.
The organelles of a cell maintain the life of a cell.
All cells are surrounded by a thin membrane called a cell membrane.
Cells have a nucleus, which contains genetic information and directs the
activities of the cell.
CA Content Standard: Biology
1. The fundamental life processes of plants and animals depend on a variety of chemical reactions that occur in
specialized areas of the organism’s cells.
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Eukaryotes- organisms whose cells contain a membrane-bound nucleus
and other membrane-bound organelles.
Prokaryotes- organisms that do not have a membrane-bound nucleus or
membrane-bound organelles.
New Vocabulary:
Organelles
Cell membrane
Nucleus
Eukaryotes
Prokaryotes
CA Content Standard: Biology
1. The fundamental life processes of plants and animals depend on a variety of chemical reactions that occur in
specialized areas of the organism’s cells.