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All forms of life share common properties
(3) Growth and
development
(1) Order
(4) Energy
processing
(2) Reproduction
(6) Regulation
(5) Response to the
environment
(7) Evolutionary adaptation
The Cell Theory
• Cells are the basic unit of structure and function in
an organism
• All cells come from prexisting cells

Robert Hooke (17th century)
–

Anton van Leeuwenhoek (later 17th century)
–

Observed microscopic organisms; organisms can be comprised of just a single cell
Schleiden (1830s)
–

Coined the phrase ‘cells’
All plants are made of cells
Schwann (1839)
–
All animals are made of cells
Cells: A Sense of Scale
10 m
Most cells and their structures are too
small to view with the naked eye.
Length of some
nerve and
muscle cells
0.1 m
Chicken egg
Unaided eye
Human height
1m
1 cm
Frog egg
Most plant and
animal cells
10 µm
Nucleus
Most bacteria
1 µm
100 nm
Mitochondrion
Smallest bacteria
Viruses
Ribosomes
Scanning EM of Enteric bacteria
on villi of small intestine
10 nm
Proteins
Lipids
1 nm
Small molecules
0.1 nm
Atoms
Electron microscope
100 µm
Light microscope
1 mm
Microscopes reveal the world of the cell
 Light microscope - 1,000x magnification, limited
resolution
– Magnification is the increase in the apparent size of an object.
– Resolution is a measure of the clarity of an image -- it is the ability
of an instrument to show two close objects as separate.
 Transmission electron (TEM) - detail of interior structures
 Scanning electron (SEM) - surface structures ‘3D image’
– Electron microscopes DO NOT allow observations of living
specimens.
© 2012 Pearson Education, Inc.
Light Microscopy
Scanning electron
microscopy (SEM) Cilia
Scanning electron
microscopy (SEM)
Longitudinal
section of
cilium
Transmission
electron
Microscopy
(TEM)
1 µm
Cross section
of cilium
1 µm
2 Basic Cell Types: Prokaryote and Eukaryote
 Bacteria and archaea are prokaryotic cells.
–
Prokaryotes have no nucleus and no true organelles.
 Eukaryotic cells = protists, plants, fungi, animals
 All cells have:
–
–
a plasma membrane
–
one or more chromosomes (DNA)
–
Ribosomes
–
cytoplasm
Only Eukaryotic cells have a
–
membrane-bound nucleus and
–
number of other organelles.
Outside of cell
Carbohydrate side chain
Hydrophilic
region
Inside of cell 0.1 µm
Hydrophobic
region
Hydrophilic
region
TEM of a plasma membrane
Phospholipid
Proteins
Structure of the plasma membrane
Prokaryotic Cell Structure
 Unicellular
 Cell Wall surrounds plasma
membrane
Fimbriae
–
Ribosome
–
Nucleoid
Plasma membrane
A typical rod-shaped
bacterium
Peptidoglycan (mix of
protein and
carbohydrates)
–
NO Cellulose (plants cells)
–
Provides structure and
support
Cell wall
Bacterial
chromosome
Composed of lipids,
carbohydrates and protein
 Nucleiod region
Capsule
–
Flagella
One large circular
chromosome that is
attached to one area of the
plasma membrane
 Flagella (Flagellum)
–
Used for directed movement
–
Rotate like propellors
Capsule
Tonsil cell
Bacterium
Endospore
Flagella
Fimbriae
h.
a.
b.
c.
d.
g.
e.
A typical rod-shaped
bacterium
Label The Following Structures:
f.
Concept Check
The three domains of life described by biologists today include
the bacteria, the archaea, and the eukarya (all other forms of
life). What is the basic difference between the eukarya or
eukaryotes and the prokaryotes (archaea and bacteria)?
a)
The prokaryotes do not have a plasma membrane
surrounding the cell.
b)
The prokaryotes use RNA and not DNA to pass on the
genetic message.
c)
The interior of the cell of eukaryotes is divided by internal
membranes into specialized compartments.
d)
The eukaryotes engage in cellular metabolism while the
prokaryotes do not.
© 2012 Pearson Education, Inc.
Answer
The three domains of life described by biologists today include
the bacteria, the archaea, and the eukarya (all other forms of
life). What is the basic difference between the eukarya or
eukaryotes and the prokaryotes (archaea and bacteria)?
–
The interior of the cell of eukaryotes is divided by internal
membranes into specialized compartments.
© 2012 Pearson Education, Inc.
Interpreting Data
Images generated by the Hubble
telescope or the planetary probes
like Voyager telescope give us a
very limited view of the universe.
Likewise, looking at cells under a
light microscope is limited by the
ability to resolve cellular parts.
Which of the following cell parts are
visible under a light microscope?
–
ribosomes
–
large macromolecules
–
microtubules
–
mitochondria—just barely
© 2012 Pearson Education, Inc.
Answer
Images generated by the Hubble
telescope or the planetary probes
like Voyager telescope give us a
very limited view of the universe.
Likewise, looking at cells under a
light microscope is limited by the
ability to resolve cellular parts.
Which of the following cell parts are
visible under a light microscope?
–
mitochondria—just barely
© 2012 Pearson Education, Inc.