Bacteria

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Bacteria VirusesBacteria Lecture

• Unit II Spring Semester

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Prokaryotes

• Unicellular organisms
• No membrane bound nucleus
• Size 1 to 3 micrometer
• Compared to a cheek cell 10 microns
• Can divide quickly
• Perfect conditions every 20 minutes1million in
  about 6 hours

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Fun facts

• 1 gram soil 2.5 billion bacteria
• More bacteria in your mouth than people on Earth
• Can be found almost everywhere

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Typical Bacteria cell
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Two kingdoms of Prokaryotes

• Archeabacteria
• No peptidoglycan cell wall
• These are the extreme prokaryotes
• Methanogens
• Halophiles
• Thermophiles
• Ancestors of Eukaryotes

• Eubacteria
• Has a peptidoglycan cell wall
• Found in the more typical places
• Ex Streptococcus, Escherichia coli

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How are bacteria categorized?
http//botit.botany.wisc.edu/images/130/Bacteria/G
rowth_Forms/Baccili_cocci.html

• Shape
• Bacilli-rod
• shaped
• Spirilla-spiral www.fused.org/science/
  cells/intro.html
• shaped
• Cocci-spherical
• shaped

http//www.vampirovibrio.com/micro/bacteria/basics
.shtml
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Shape continued
www.ustboniface.mb.ca/.../Biologie/
Taxinomie/pg2.htm
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What are these shapes?

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Gram staining Gram positive or negative?shape?
http//www.ha.org.hk/qeh/dept_pathology_dept_micro
2b.htm
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How are bacteria categorized?Gram staining1st
stain is violet (stains the peptidoglycan cell
wall)2nd stain or counter stain is red (stains
the lipid and carbohydrate layer)

• Gram positive bacteria
• Appear violet

• Gram negative bacteria
• Appear pink

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How are bacteria categorized?

• Movement
• Flagella slime layer

http//www.zetacorp.com/biocorrosion.shtml
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Nutrition in bacteria

• Most bacteria are heterotrophs
• Most are saprophytic (Greek sapros rotton or
  putrid)
• Activities release nutrients make available to
  plants then animals
• Some are symbiotic
• parasitic, commensalistic, mutualistic

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Nutrition in bacteria

• Chemosynthetic Autotrophs
• Obtain energy from the oxidation of inorganic
  compounds
• Only group that can do this
• Photosynthetic Autotrophs
• Cyanobacteria (aka blue green alga)
• Red sea named after
• this bacteria

www.cc.u-ryukyu.ac.jp/ coral/Terpios-2.htm
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Respiration in bacteria

• Aerobes-normal cell respiration
• Anaerobes-
• Ex botulism
• EX tetanus

http//www.agooart.com/parody/
www.nwhc.usgs.gov/.../avian_botulism/
avian_botulism.html
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Reproduction

• Binary fission
• Simple cell
• division (not mitosis)
• Can happen very
• fast in 15-20 min.

www.brooklyn.cuny.edu/bc/ahp/MBG/
MBG3/BinaryFission.01A.htm
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What conditions retard reproduction?

• Crowding
• Competition for food
• Accumulation of waste
• Competitive digestive enzymes
• Bacteria continue to grow until these conditions
  cause the death rate to equal reproductive rate.

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Conjugation bacteria sex
http//www.sp.uconn.edu/terry/images/anim/Fmating
.gif
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Conjugation bacteria sex

• Bacterial chromosome
• contains all genes necessary
• for growth reproduction.
• Extra genetic information
• is on plasmids
• Two types
• F
• R
• Hfr

www.liu.edu/.../micro-web/html-files/
ChapterD-2.html
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Endospores

• When times are tough some bacteria form
  endospores
• Resist drought, radiation, heat, chemicals
• Botulalism (obligate anaerobe)

www.apsnet.org/.../PhotosE-H/ endospore.htm
www.microbe.org/microbes/ spores.asp
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Toxins

• Endotoxin
• Exotoxin

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Good guys vs. Bad guys