Bacteria
Chapter 19
What is a Prokaryote?
An organism with
no nucleus and
unicellular.
ALL BACTERIA!
Classifying Prokaryotes
• Two main groups:
1. Eubacteria
a. biggest group
b. live almost everywhere
c. peptidoglycan cell wall
2. Archaebacteria
a. no peptidoglycan cell wall
b. live in harsh (really hot) environments
Bacteria Shapes
• Shape: Bacillus (rod), coccus (sphere)
and spirillum (spiral)
(chains)
(Pairs)
(clusters)
Metabolic Diversity
Heterotrophs
Cannot make own
food; need to take in
organic molecules
• Decomposers
Autotrophs
Can make own organic
food from CO2
molecules with light or
other compounds
1. Photoautotrophs
• Cyanobacteria
2. Chemoautotrophs
• Nitrifying bacteria
Energy Release
• Two ways: respiration or fermentation
• Classified based on how they release
energy from food:
Aerobes – cell respiration only
Anaerobes – fermentation only
Facultative anaerobes – can do both
but prefers fermentation
Growth and Reproduction
• Binary Fission –
simple mitosis
• Conjugation –
swapping genetic
material
Bacterial Importance
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Photosynthesis
Decomposers – sewage treatment
Nitrogen Fixers – fertilizer for plants
Biological – fiber breakdown
Genetic Engineering – production of
hormones for medical purposes
Bacterial Disease
• Pathogen – any disease causing agent
• Causes cell and tissue destruction of
infected organism (food for bacteria)
• Release of toxins that poison the host and
cause symptoms of disease.
Examples: Tuberculosis, anthrax, E. coli,
salmonella, tetanus, syphilis
Prevention and Control
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Vaccines – given to prevent illness
Antibiotics – given after infection to kill bacteria.
Sterilization – exposure to high heat
Disinfectants – chemical solutions kill
Refrigeration – cold temps slow growth
Cooking – high temps kill
Canning and Preservatives – chemicals and
lack of oxygen