Living organisms are divided into 3 Domains

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Living organisms are divided into 3 Domains

• The broadest classification
• There are 3 groups
• Bacteria
• Archea Bacteria
• Eukaryote

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Relative sizes
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Bacteria

• Are prokaryotic
• Have DNA in a nucleoid region
• Lack most organelles

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Archea bacteria

• Live in extreme conditions
• Biologists refer to these bacteria as
  extremophiles meaning lovers of the extreme

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Bacteria

• Has a cell wall
• Plasma membrane
• Ribosome
• DNA in nucleoid region
• Flagella

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Structure of Bacteria

• Bacteria come in 3 shapes
• Cocci are spherical
• Bacilli are rod shaped
• Spirilla are spiral shaped
• Spirochetes are the largest spiral shaped
  bacteria
• Causes Lyme Disease

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Cell Wall Structure

• Almost all bacteria have one
• Cell walls function as protection
• There are 2 types
• One is comprised of peptidoglycan
• Other has less peptidoglycans and an additional
  membrane

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Bacteria Motility

• Half are motile
• Move towards/away from signals from environment
• Most have flagellum
• Others have pili which are shorter and thinner
• Help bacteria stick to each other and objects

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Bacteria Reproduction

• Reproduce by binary fission
• Can copy themselves every 20 minutes
• In 12 hours 1 cell can become 68 billion cells!

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Genetic mixing (recombination)

• Transformation
• Bacteria take up pieces of RNA from the
  environment and incorporate them into their DNA
• Conjugation
• 2 cells temporary join and directly transfer
  information
• Plasmids are separate pieces of DNA that are
  exchanged
• Transduction
• Viruses infect bacteria and inject their genes

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Prokaryotic Cells (Bacteria)

• Very diverse group
• Can be harmful
• Mycobacterium tuberculosis causes TB
• Streptococcus pyogenes causes strep throat
• Can be helpful
• E. coli lives in your intestines and releases
  vitamins
• Other kinds live in your mouth and prevent fungi
  growth

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How Bacteria cause illness

• Pathogens are microorganisms that cause disease
• Some invade tissues and destroy cells
• TB is due to bacteria that destroy the white
  blood cells that engulf them

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Defense against bacterial disease

• The major reason for decline in disease is due to
  better hygiene and public health measures
• Washing hands and dishes
• Careful preparation of food
• Water quality

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The bodys defenses

• Skin and mucous lining of mouth nose and
  digestive system
• The use of antibiotics
• Many prevent the growth of cell walls
• There is concern about the overuse of antibiotics
  because the bacteria are forming a resistance
  against the antibiotics
• Mersa and VRE are bacteria that resist most
  antibiotics

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Helpful Bacteria

• There are some bacteria that are helpful for
  humans

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Cyanobacteria

• Photoautotrophic modes are very ancient
• Cyanobacteria
• Generates oxygen as a waste product of their
  photosynthesis

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Chemical Recycling

• Many bacteria play an important role in
  decomposition
• Heterotrophic prokaryotes consume organic wastes
  and return carbon to the atmosphere
• Some species convert gas in the air into nitrogen
  compounds in soil and water used by plants
• All nitrogen that plants use to make proteins and
  nucleic acids were first processed in prokaryotes

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Human uses

• Bioremediation
• The use of organisms to remove pollutants from
  soil water and air
• Examples
• Use of anaerobic prokaryotes to decompose organic
  compounds in sludge at a sewage plant
• Pseudomonas is a bacteria that cleans up oil
  spills
• Thiobacillus thrives in acidic waters and
  extracts lead and mercury from mine runoff