Download Bacteria

Bacteria
Characteristics of Bacteria.
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Smallest and simplest living thing
Have no organelles, including no nucleus
Genetic material = simple circular chromosome
They have cell walls to protect them from outside
pressure
• Transmitted through:
– air
– Water
– Human
Contact
– Contaminated
Food
Bacterial Shape & Arrangement
SHAPES:
• Coccus: round
• Bacillus: rod shaped
• Spirillum: spirals
ARRANGEMENTS:
• Diplo: pairs
• Staphylo: clusters
• Strepto: chains
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
w/o oxygen
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
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)
Bacterial Reproduction
BINARY FISSION:
• Asexually Reproduction
• 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 Pilli
• Occurs when threatened,
• Hope to pass on
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genetic material
– Will make the
bacteria
resistant
to changes.
Immune Response in Humans.
• I.S. fights off
invaders which
are called
ANTIGENS
• Our bodies
produce
ANTIBODIES
against each
antigen
• Antibodies lock
on to the
pathogen’s
active site or
prevent its
attachment
Types of immunity
• Resistance to Disease
Passive Immunity:
• Antibodies are:
– Acquired
– Passed from mother to
child
– Injected
Active Immunity:
• Exposure to antigen:
– Recovery of disease
– Through vaccination
Vaccination:
• Injection of:
– Weakened Antigen
– Pieces of antigens
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!