 While we watch the YouTube clip, take notes about the
scientists involved in the discovery of cells. Note the
dates, people involved, and their particular discoveries.
 http://www.youtube.com/watch?v=dscY_2QQbKU&fe
ature=related
 On a left-side sheet of notebook paper, using your
notes from the video, along with your textbook, create
a timeline leading up to the cell theory. Illustrate each
discovery (use color). Leave enough space between
events to add details later.
 Hooke-English scientist who was the first to see a
dead cell while viewing cork under a microscope.
 Coined the term “cell”.
 Leeuwenhoek- Dutch scientist who was first to see
living cells in a drop of pond water.
 Considered the “Father of Microscopy”.
 Schleiden- German botanist who stated all plants are
composed of cells.
 Schwann-German zoologist who stated all animals are
composed of cells.
 Virchow-German physician who saw bacterial cells
dividing under microscope.
1) All living organisms are composed of one
or more cells
2) Cells are the basic units of structure and
function in an organism
3) Cells come only from the reproduction of
existing cells
Which of the 7 characteristics of life do the
parts of the Cell Theory match up with?

Size
Most plant and animal cells are about 10-50
micrometers (µm) in diameter. Most bacterial
cells are about 1-10 µm in diameter.
 Cells are limited by their surface area to
volume ratio.


As a cell grows, its volume increases much faster
than its surface area.
http://learn.genetics.utah.edu/content/begin/
cells/scale/
 Why is surface area so important to
determining the health and survival of a cell?


Surface Area to Volume Ratio
 Everything that the cell needs or has to get
rid of has to go through the cell membrane,
the amount of which relates to the surface
area.
 The amount of food needed or waste
produced depends on the volume.
 As a cell gets bigger there will come a time
when its surface area is insufficient to meet
the demands of the cell's volume and the
cell stops growing.
 Shape
Cells come in a variety of shapes.
 The diversity of form (structure) reflects a
diversity of function.
 How do the shapes of nerve, blood, and
skin cells suit their function?


Plasma membrane


Cytoplasm



Covers cell surface and acts as a boundary between
inner contents of a cell and its environment
Region of the cell inside the membrane
Includes fluid, cytoskeleton, and all organelles
(except the nucleus)
Control center

Region containing DNA which regulates cell
construction and other processes
 Prokaryotes
Cells without a
nucleus or
membrane bound
organelles (MBOs)
 Example: E. coli

 Eukaryotes
Cells with a nucleus and membrane bound
organelles (MBOs)
 Examples: Human cheek cells, plant cells


Colonies
Colonial organisms are collections of genetically
identical cells that live together in a group.
 Not truly multicellular because few activities are
coordinated.


True Multicellularity

Cells of multicellular organisms are organized
further into tissues, organs, and organ systems,
which have their own specific purposes.