Transcript BIO 1011 Dr. Lee Science Center 227 Phone: (610) 660

BIO 1011
Dr. Lee
Science Center 227
Phone: (610) 660-3439
[email protected]
Levels of Biological Organization
What is a cell?
Discovered by Robert Hooke, 1655
Microscopic Analysis of cork sections
Tiny “Chambers” = “Cells”
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
Wikipedia
What is the “Cell Theory”?
• Cells are the universal building blocks of life
• Cells arise from pre-existing cells
What defines something as “living”?
How big is a cell?
A Sense of Scale
Figure 1-6
01_06_What can we see.jpg
“What can we see?”
“What can we see?”
Metric Units
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One meter - About Three Feet
One mm - 1/1000 of a meter
One µm - 1/1,000,000 of a meter
One nm - 1/1,000,000,000 of a meter
mm = 10-3 m
µm = 10-6 m
nm = 10-9 m
How to look at cells
• Light microscopy
• Electron microscopy
How to look at cells
• Light Microscopy
– Resolution of about 0.2 m
• Resolution - How close two objects can be
together and still be seen as 2 objects
Light Microscopy
Fixed and stained
Live cell
The History of Cell Visualization:
Eduard Strasburger, 1880:
01_04_Early microscopes.jpg
Modern day light microscopy:
How to Look at Cells
• Electron Microscopes
• Two types:
– Scanning
• 3-D image of cell’s surface
• Resolution of 3 nm
– Transmission
• Interior cell structure
• Resolution of 2 nm
• Higher resolution because of shorter wavelength
SEM of a protozoan (single
celled eukaryote)
Fig. 1-32
TEM micrograph of
a killer T cell
preparing to attack a
large tumor cell
TEM Micrograph of
Mammalian Cell
Basic Cell Anatomy
Basic Cell Anatomy
Plasma Membrane
Cytoplasm (cytosol: soluble portion)
Two major cell types
Prokaryotic
Eukaryotic
A Basic Distinction: Prokaryotic and Eukaryotic Cells
“Pro” = before
“Eu” = true
Distinguishing features:
The world of prokaryotes: Eubacteria and Archaea
The diversity of prokaryotes
The common
bacterium: Escherichia
coli (E. coli)
Cells range in sizes
Flagellum
Ribosomes
in cytosol
DNA
Plasma
Membrane
Cell wall
Panel 1-2
Plant vs animal vs bacterial cell size
The Eukaryotic Cell:
Nucleus
Mitochondria
(chloroplasts)
Internal Membranes generate intracellular compartments
ER
Golgi
Lysosomes
Peroxisomes
Vesicles
Cytosol
Cytoskeleton
Miniature
Factory
Engine
Fig.1-5
Key concepts you need to
know
• Unity within Diversity
• The role of microscopy in cell visualization
Panel 1-1, Page 8 (basics)
• The fundamental basis of cell classification
Eukaryotic and Prokaryotic
• The subcellular components of the
eukaryotic cell
PANEL 1-2, Page 25