Download Prokaryotic Cell Structure and Function

Prokaryotic Cell Structure
and Function
Size of Bacteria
• Average bacteria 0.5 - 2.0 um in diam.
– RBC is 7.5 um in diam.
– Pulopiscium fishelsoni, bacillus (80µm in
diameter and 200-600 µm long)
– Thiomargarita namibiensis, sperical (100750 µm in diameter.)
Shapes of Bacteria
•
•
•
•
•
•
Coccus
Bacillus
Coccobacillus
Vibrio
Spirillum
Spirochete
Spherical Bacteria
An average coccus is about
0.5-1.0 micrometer (µm) in
diameter.
•
Streptococcus pneumoniae,
A. Division in one plane.
• Diplococcus: cocci
arranged in pairs
• Streptococcus: cocci
arranged in chains
•
Streptococcus pyogenes,
Spherical Bacteria
B. Division in two planes.
• tetrad: cocci
arranged in squares
of 4
C. Division in three
planes
• Sarcina: cocci in
arranged cubes of 8
sarcina
Spherical Bacteria
D. Division in random
planes
• Staphylococcus:
cocci arranged in
irregular, often
grape-like
clusters
Rod-Shaped Bacteria
• Diplobacillus
• Coccobacillus
• Streptobacillus
Spiral-Shaped Bacteria
• Spirochete
• Spirillum
Cell Structures
• Cell Membrane
• Cytoplasm
• Cell Wall
• Components external to cell wall
– Flagella
– Pili
– Capsule/ Slime layer
Cell Membrane
• Hydrophobic Proteins
• Bilayer Phospholipid
– Triclosan-enoyl transferase
• Hopanoids
Membrane proteins
• Structural support
• Detection of environmental
signals
– ToxR- Vibrio cholera
• Secretion of virulence factor and
communication signals
– NodI and NodJ-Rhizobia
Membrane lipids
• Phosphoryl heads
– Negative-phosphatidate
• Phosphatidylglycerol
• Cardiolipin
– Positive-Phosphatidylethanolamine
• DNA interaction
• transporter protein
• Fatty acids
– Saturated straight chain (6-22)
– Unsaturated
• Oleic acid (cis)
– Cyclopropane