Download Chapter 7: Cell Structure and Function and Function

Unit 3: The Cell
Chapter 7:
Cell Structure and Function
and Function
7-1
Section Outline
7-1: Life is Cellular
A) The Discovery of the Cell
1)
The Cell Theory
2)
Early Microscopes
B) Exploring the Cell
1) Light Microscopes
and Cell Stains
2) Electron Microscopes
C) Prokaryotes and
Eukaryotes
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A -1
1)
A) The Discovery of the Cell
The Cell Theory
- All living things are made up of cells.
- Cells are the basic units of structure and function in living
things.
- New cells are produced only from existing cells.
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A -2
A) The Discovery of the Cell
2) Early Microscopes
!
In 1665, Englishman
Robert Hooke used an
early compound
microscope to look at
a nonliving thin slice of
cork, a plant material.
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A) The Discovery of the Cell
2) Early Microscopes
!
Under the microscope, cork
seemed to be made of
thousands of tiny, empty
chambers that Hooke called
“cells”. The term cell is used in
biology to this day.
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A) The Discovery of the Cell
2) Early Microscopes
!
In Holland, Anton van
Leeuwenhoek examined
pond water and other
things
!
He drew the organisms he
saw which today we call
bacteria.
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A -5
A) The Discovery of the Cell
These discoveries are the cell theory, a fundamental
concept of biology.
!
The cell theory states:
!
•
•
•
All living things are made up of cells.!
!
Cells are the basic units of structure
and function in living things.!
!
New cells are produced from existing
cells.
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B -1
B) Exploring the Cell
1) Light Microscopes and Cell Stains
A light microscope allows light
through a specimen and uses
two lenses
!
The first lens, located just
above the specimen,
produces an enlarged image
!
The second set of lenses
magnifies this image even
more
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B) Exploring the Cell
1) Light Microscopes and Cell Stains
•
•
•
Light microscopes can
produce clear images
only to a magnification of
about 1000 times
Most living cells are
nearly transparent (see
through)
Using chemical stains or
dyes can solve this
problem.
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B) Exploring the Cell
1) Light Microscopes and Cell Stains
•
Some dyes give a
particular color when
viewed under specific
kind of light. This is
fluorescence.
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•
B) Exploring the Cell
1) Light Microscopes and Cell Stains
Fluorescent dyes can be attached to specific
molecules and can then be made visible using a
special fluorescence microscope.
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B) Exploring the Cell
1) Light Microscopes and Cell Stains
•
Fluorescence microscopy
makes it possible to see
the locations of these
molecules, and even to
watch them move about in
a living cell.
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B) Exploring the Cell
2) Electron
Microscope
•
•
•
•
Use beams of
electrons, not light,
Focused by
magnetic fields.
Much higher
resolution than
light microscopes.
Samples must be
placed in a
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B) Exploring the Cell
2) Electron
Microscope
!
•
•
Researchers chemically preserve their samples first
Electron microscopy can be used to examine only
nonliving cells and tissues.
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C) Prokaryotes and
Eukaryotes
Eukaryotes are cells that enclose their DNA in a nucleus.
!
Prokaryotes are cells that do
not enclose DNA in a nucleus.
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C) Prokaryotes and
Eukaryotes
The nucleus is a structure
that contains the cell’s
genetic material (DNA). The
nucleus controls many of
the cell’s activities.
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C) Prokaryotes and
Eukaryotes
1) Prokaryotes
•
•
generally smaller and
simpler than eukaryotic
cells.
The organisms we call
bacteria are prokaryotes.
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C) Prokaryotes and
Eukaryotes
2) Eukaryotes
•
•
•
are generally larger and
more complex than
prokaryotic cells.
contain dozens of
structures and internal
membranes
are highly specialized.
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•
C) Prokaryotes and
Eukaryotes
2) Eukaryotes
There are many types of eukaryotes: plants, animals, fungi,
and organisms commonly called “protists.”