Bacteria

Kingdom Archaebacteria Prokaryotes Single celled Cell Wall (does not have peptidoglycan) Live in harsh environments 3 major groups 1) methanogens – swamps, digestive tracts 2) halophiles – salty areas 3) thermoacidophiles – hot & acidic areas

Kingdom Eubacteria Prokaryotes Single celled Cell wall with peptidoglycan Can live almost anywhere

3 major bacterial shapes 1)Cocci – round 2)Bacilli – rod 3)Spirilli – spiral Other terms about bacterial arrangements 1)Strep = chains 2)Staphylo = clusters

Bacteria are classified according to 1)Cell wall composition (gram staining) 2)Evolutionary relationship (phylogeny) 3)Shape 4)Motility (how they move) 5)Genetics/DNA 6)Metabolism (autotroph or heterotroph)

Gram Staining Uses 2 colored stains to determine the amount of peptidoglycan in the bacterial cell walls Gram + = purple, peptidoglycan, penicillin Gram - = red/pink, low peptidoglycan

Helpful bacteria Most (about 90%) of all bacteria are harmless or helpful to us. Can be used for: 1) foods (cheese, buttermilk, yogurt, etc…) 2) decomposers 3) used in industry

Harmful bacteria Some bacteria can be pathogens (disease causing) Bacterial infections & diseases strep throatfood poisoning (botulism) gonorrheatuberculosis salmonellalyme disease tetanus

What makes some bacteria harmful? 1) toxins (Exotoxins- are released by living bacteria Endotoxins- are released when the bacteria die) 2) the bacteria destroy tissues

How do we treat bacterial infections? ANTIBIOTICS – drugs that inhibit or kill bacteria There are several types of antibiotics. Some are made from fungi or other bacteria.

Problems caused by antibiotics 1)Antibiotic resistance 2)Some people have reactions to antibiotics

Special structures Capsules – some bacteria form a hard outer covering to protect them from drying out or your bodies immune system Pili – short, ahir-like structures on the bacterial surface, used to help bacteria “stick”.

3) Endospores – another covering that protects the bacteria from a harsh environment, allows the bacteria to go dormant. 4) Flagella – whip-like tail to help with movement

Bacteria & reproduction Reproduce asexually by binary fission Reproduce sexually by conjugation (exchange genetic information between 2 bacteria)

How bacteria get their energy 1)Heterotrophs saprophytes – decomposers 2) Autotrophs photoautotrophs – photosynthesis (no chloroplasts!!)

Some bacteria need oxygen – obligate aerobes Some bacteria die around oxygen – obligate anaerobes Some bacteria can live with or without oxygen – facultative anaerobes