Bacteria

Kingdom Archaebacteria

ProkaryotesSingle celledCell Wall (does not have peptidoglycan)Live in harsh environments3 major groups

1) methanogens – swamps, digestive tracts2) halophiles – salty areas3) thermoacidophiles – hot & acidic areas

Kingdom Eubacteria

ProkaryotesSingle celledCell wall with peptidoglycanCan live almost anywhere

3 major bacterial shapes

1) Cocci – round2) Bacilli – rod3) Spirilli – spiral

Other terms about bacterial arrangements1) Strep = chains2) Staphylo = clusters

Bacteria are classified according to

1) Cell wall composition (gram staining)2) Evolutionary relationship (phylogeny)3) Shape4) Motility (how they move)5) Genetics/DNA6) Metabolism (autotroph or heterotroph)

Gram Staining

Uses 2 colored stains to determine the amount of peptidoglycan in the bacterial cell walls

Gram + = purple, peptidoglycan, penicillinGram - = 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 & diseasesstrep throat food poisoning (botulism)gonorrhea tuberculosissalmonella lyme diseasetetanus

What makes some bacteria harmful?1) toxins

(Exotoxins- are released by living bacteriaEndotoxins- 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 resistance2) 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) Heterotrophssaprophytes – decomposers

2) Autotrophsphotoautotrophs – 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