210 likes | 678 Views
2. Eubacteria. “true” bacteria microscopic ex cyanobacteria (blue-green algae) on earth for over 3 billion years able to carry out photosynthesis (produces oxygen) oxygen conc of atmosphere increased allowing oxygen breathers (animals) to survive. Uses of Eubacteria. digestion in intestines
E N D
2. Eubacteria • “true” bacteria • microscopic • ex cyanobacteria (blue-green algae) on earth for over 3 billion years • able to carry out photosynthesis (produces oxygen) • oxygen conc of atmosphere increased allowing oxygen breathers (animals) to survive
Uses of Eubacteria • digestion in intestines • yoghurt/cheese production • fermentation (wine, beer, pickling…) • wastewater/oil spill/toxic spill treatment • BiologySource • decomposers
Dangerous Eubacteria • cause health problems: • strep throat • food poisoning (E. coli and salmonella)
Structure & Function of Bacteria • microscopic • smallest living cells • classified according to: • cell shape • cell wall structure • motility (way of moving)
1. Cell Shape • 3 basic cell shapes • spherical – “cocci” • rod-shaped – “ bacilli” • spiral – “spirochetes”
prefixes are added to show living arrangement of bacteria • strepto – chain • stphlyo - cluster
CAN YOU NAME IT??? diplococcus staphylococcus streptococcus
2. Cell Wall Structure • 2 kinds of cell walls, appear different when stained with Gram stain • peptidoglycan – thick coat of sugars, makes wall strong & rigid (Gram postive) • less peptidoglycan (Gram negative)
Movement • various methods: • most mobile bacteria use flagella (whip-like tail) • others secrete mucous can glide on
How Bacteria Reproduce • Asexual - Binary Fission • 1 original cell splits into 2 • can occur in 20 minutes for many bacteria species. • In 12 hours, 1 bacterium can divide to form a colony of 68 billion cells. • overcrowding, waste, and food availability do not allow populations to grow this large. • produces colonies of bacteria that are genetically identical.
2. Types of Sexual Reproduction • Transformation: bacteria pick up stray DNA from their surroundings. • Conjugation: two bacterial cells join (= conjugate) to exchange genetic material (plasmids, separate from main DNA)
3. Transduction: viruses that infect bacteria transmit genetic material from another source • Endospores form when environmental conditions make normal functions too difficult.