Bacteria
• All Single-celled prokaryotes without nucleus!!
Two Kingdoms of Bacteria:
1. Kingdom Archaebacteria –
anaerobic bacteria that live in “extreme” environments
Believed to be the ancestor the eukaryote cells
Examples are
Thermophiles-heat loving
Halophiles-salty loving
2. Kingdom Eubacteria –
all other bacteria; usually aerobic (most common)
Both bacteria and viruses can be harmful or harmless
ie. Yogurt
Bacteria cause illness by releasing toxins that harm body cells.
Destroy cells as they grow & multiply
Shapes of Bacteria
1. Coccus (cocci=plural) – SPHERE shape
2. Bacillus (bacilli=plural) – ROD shape
3. Spirillum (spirilla=plural) – SPIRAL shape
Patterns of Growth
1. Strepto- = chain of cells
2. Staphylo- = cluster of cells
3. Diplo- = paired cells
Important structures of bactria
1. DNA (circular, not in a nucleus)
2. Cell wall!!!!!
3. Capsule – sticky layer around cell wall
• help attach to surfaces
• protects against white blood cells
4. Flagellum –whip-like tail or cilia with short hair-like that helps in movement
5. Antigens-on surface
How do bacteria reproduce?
1. Binary fission –bacterium copies itself & divides into two
• asexual reproduction outside host
• makes identical bacteria
2. Conjugation –bacterium transfers plasmids, all or part of DNA to another bacterium using
pili
• sexual reproduction
• non-identical bacteria