bacteria
TRANSCRIPT
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