Download Bacteria

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)
2)
3)
4)
5)
6)
Cell wall composition (gram staining)
Evolutionary relationship (phylogeny)
Shape
Motility (how they move)
Genetics/DNA
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 throat food poisoning (botulism)
gonorrhea tuberculosis
salmonella lyme 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