Bacteria

Classificationunicellular prokaryotes

2 Domains• Achaea

– Kingdom Archaebacteria (ancient)– found in marshes, swamps, hot sulfur

springs, Great Salt Lake, deep ocean vents • Bacteria

– Kingdom Eubacteria (true)– found in almost any habitat

Bacteria

Classification

Kingdom Archaebacteria

• cell walls without peptidoglycan (carbohydrate)

• autotrophic or heterotrophic

• live anaerobically

• live in harsh environments (great salt lakes, hot springs)

• ex: Methanogens (in digestive tract of animals), Halophiles (salt-loving)

Bacteria

Classification

Kingdom Archaebacteria

• cell walls without peptidoglycan (carbohydrate)

Bacteria

Classification

Kingdom Archaebacteria

• live in harsh environments (great salt lakes, hot springs)

Bacteria

Classification

Kingdom Eubacteria

• cell wall contains peptidoglycan (carbohydrate)

• autotrophic or heterotrophic

• free living (ponds, streams, on dead organisms) or deadly parasites

• ex: streptococcus, Escherichia coli, anabaena

Bacteria

Classification

Kingdom Eubacteria

• ex: streptococcus, Escherichia coli, anabaena

Bacteria

Cell structure

• cell wall

• nucleic acid

• capsule

• flagella

• pili

• ribosomes

• plasmid

Bacteria

Cell structure

• endospore– tough protein coat formed inside cell; used to

survive harsh conditions

Bacteria

Classifying Bacteria

bacteria are classified according to:

• shape

• arrangement

• staining properties

Bacteria

Classifying Bacteria

shape

• spherical– coccus/cocci

• rod– bacillus/bacilli

• spiral– spirillum/spirilli

Bacteria

Classifying Bacteria

arrangement

• pairs– diplo…

• clusters– staphlo…

• chains– strepto…

Bacteria

Classifying Bacteria

arrangement

Bacteria

Classifying Bacteria

staining properties

• gram stain negative

– thin layer of peptidoglycan

– stains pink

• gram stain positive

– thick layer of peptidoglycan

– stains purple

Bacteria

Life processes

nutrition

• heterotrophs

– parasitic

• ex: staphylococcus aureus

– saprophytic

Bacteria

Life processes

nutrition

• photosynthetic autotrophs

– energy from sunlight

– ex: anabaena

Bacteria

Life processes

nutrition

• chemosynthetic autotrophs

– energy from chemicals

– ex: Nitrobacteria

Bacteria

Life processes

respiration• obligate aerobes

– require O2 to live– ex: tuberculosis

• obligate anaerobes– can not live in presence of O2

– ex: botulism • facultative anaerobes

– lives with or without O2

– ex: E. Coli

Bacteria

Life processes

reproduction

• binary fission

– split in two (asexual reproduction)

Bacteria

Life processes

reproduction

• conjugation– transfer of genetic material to an acceptor bacterium– sexual reproduction

Bacteria

Life processesreproduction• spores

– buds form and produce new cells– spores can survive a long time before

“hatching”

Anthrax spores

Bacteria

Advantages of bacteria• human intestine• food production-

– milk, buttermilk, yogurt, sour cream, cheese• ecology

– decomposers– nitrogen fixation

• producers

Bacteria

Disadvantages of bacteriadiseases

Bacteria

Disadvantages of bacteriadiseases• most bacteria affect host be producing toxins• endotoxin

– toxic substance bound to cell wall• exotoxin

– secreted substance toxic

treatment• antibiotics

– medication used to help kill or assist immune system in destruction of bacteria

Bacteria