Bacteria

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Bacteria

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Characteristics of Bacteria

• Smallest and simplest living thing
• Have no membrane bound organelles, including no
  nucleus
• Genetic material simple circular chromosome
• They have cell walls to protect them from outside
  pressure
• Transmitted by
• air
• Water
• Human Contact
• Contaminated Food

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Bacterial Shape Arrangement

• SHAPES
• Coccus round
• Bacillus rod shaped
• Spirillum spirals
• ARRANGEMENTS
• Diplo pairs
• Staphylo clusters
• Strepto chains

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Feeding Requirements

• Some are heterotrophs live as parasites
• Some feed on dead material saprobes
• Some are photosynthetic autotrophs

Strep throat bacteria
Blue-green bacteria
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Types of Metabolism

• Obligate aerobes
• require oxygen to live
• Example E.coli lives in mammal intestines
• Obligate anaerobes
• Killed in the presence of oxygen
• Example Syphillis
• Facultative aerobes
• can live with or without oxygen

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Bacterial Adaptations for Survival

• ENDOSPORES
• Hard, outer covering produced during harsh
  environments
• Resistant to
• drying out
• boiling
• Metabolism slows down inside endospore
• Resumes growing when conditions are more
  favorable

Endospore
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• TOXIN PRODUCTION
• Some bacteria produce poisons when the Endospore
  begins to grow
• Toxins kill off other bacteria
• providing more food for the surviving bacteria
• Some toxins are deadly
• Examples
• Botulism (food poisoning)
• Tetanus (lock jaw)

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Bacterial Reproduction

• BINARY FISSION
• Asexually Reproduce
• Splitting in ½ after copying the DNA
• Occurs very quickly
• Will stop reproducing only if
• Run out of food
• Dry up
• Poisoned by own wastes

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• CONJUGATION
• Sexual Reproduction
• Transfers all or part of the DNA between 2
  bacteria
• Transfer through a projection called a Sex Pilli
• Occurs when threatened
• Hope to pass on genetic material
• Will make the bacteria resistant to changes

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Some helpful uses for bacteria

• NITROGEN FIXATION Some bacteria convert
  nitrogen gas into nitrates in the soil which is
  necessary for plant growth
• The bacteria live in association with the plant
  roots
• SAPROBES Break down dead organic matter

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Bacterial Uses

• FOOD FLAVORINGS
• Food flavors are produced by
• Fermentation
• Bacterial wastes, etc.
• EX Vinegar, yogurt, butter, cheese, pickles,
  buttermilk, sauerkraut
• ANTIBIOTIC PRODUCTION
• Some bacteria produce antibiotics that will kill
  other forms of bacteria
• Antibiotics kill bacteria only!