Bacteria

Bacteria

Kingdoms Archaea & Eubacteria

Two Kingdoms of Bacteria• Two Kingdoms

– Archaea (Archaebacteria)- Extreme Bacteria– Eubacteria- True Bacteria

• Why seperated into two kingdoms?– Cell wall of peptidoglycan- Eubacteria

Cell wall of unique lipids- Archaea• Different RNA base sequences• React differently to antibiotics

• Eubacteria-susceptible Archaea- resistant

• Why were they at once one kingdom (Monera)• Similar size and shape• Prokaryotic

Archaebacteria TypesArchaea Type Environment

Mesophiles 20-45 C

Thermophile Above 60 C

Acidophile pH 1-2

Alkophile Ph9-11

Halophiles 5-20% salt

Psychrophiles Below 15 C

Barophiles High Pressure

Methanogens Swamps; intestines of organisms

Archaebacteria

Archaebacteria Locations

Salt Lake in Kenya- The red color of the lake is caused by halophiles

Heat Vent in Yellowstone the red on the rocks is thermophiles

Methanogens located in swamps & intestines of organisms

Evolution of Archaea

Archaea diverged totally separate from other bacteria and from eukaryotes

Eubacteria• Defining Characteristics

– Prokaryotic unicellular– Cell Wall of Peptidoglycan – Most heterotrophic; some autotrophic– Smaller ribosomes and circular chromosomes

• Placed into three main groups:– Heterotrphic (absorb nutrients or are saprobes)– Autotrophic-photosynthetic- Cyanobacteria– Autotrophic-chemosynthetic

Cyanobacteria

Chlorophyll is not contained in chloroplasts but rather is located in the cytoplasm

Eubacteria Shapes

CocciSpirilla

Bacilli

Eubacteria Arrangement

Strept Staph

Diplo

Bacteria Structure

Gram Positive vs Gram Negative• Appear Purple when

stained• Retain the violet Gram

stain• Thick peptidoglycan cell

wall• Some produce endospores• Produce exotoxins• Exp: Streptococcus;

Staphalococus; Lactobacilli; Clostridium botulinum and tetani; Mycobacterium tuberculosis

• Appear Pink when stained• Lose the violet Gram stain and

pick up the pink counterstain (Safranin)

• Thinner peptidoglycan cell wall• Additional Membrane outside

cell wall• Produce endotoxins• Exp: E. coli; Enteric bacteria;

nitrogen-fixing bacteria; chemoautotrophs; Salmonella; Neisseria gonorrhoeae

Gram Positives and Negatives

Bacteria Respiration• Obligate aerobes

– Must have oxygen in order to survive– M. tuberculosis

• Faculative anaerobes– Flourish in conditions without oxygen but can

survive with oxygen

• Obligate anaerobes– Are poisoned in the presence of oxygen– Clostridium tetani; Clostridium botulinum;

syphilis

Endospores• Produced by some bacteria when in

unfavorable conditions- dormant state

• Hard outercovering that is resistant to drying out, chemicals, and boiling.

• When encountering favorable conditions it resumes growth and reproduction

• Clostridium botulinum; C. tetani

Bacteria Reproduction• Binary fission- asexual method in which

chromosome is copied; cell grows; cell divides w/ one chromosome copy in each cell– Very rapid process- 20 min!

Conjugation • Process in which one bacterium transfers all or

part of its chromosome to another cell through the pili.

Other reproductive methods• Transformation- bacteria cell takes in DNA

from external environment. New DNA is substituted into the chromosome

• Transduction- Virus obtains fragment of DNA from host bacteria and when it infects another bacteria it releases the fragment into the new bacteria

Toxins• Endotoxins-

– produced by Gram negative bacteria– Not released until the bacteria is dead– Cause fever, body aches, weakness and can

damage blood vessels

• Exotoxins– Produced by Gram positive bacteria– Produced while bacteria is living– Affect nerve and muscle tissue