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BACTERIA
• Bacteria
on the
tip of a
pin!
Composed of
• One, circular chromosome
• Plasma membrane
• Ribosomes
• Cell wall with
peptidoglycan
Composed of
• Some have
– Capsule
• Slimy outer layer
– Flagella
– Pili
• Straw-like extensions
• Allow bacteria to stick to host
• Some allow conjugation
– Exchange of plasmids
Flagella
Conjugation
Composed of
• Some have
–Plasmids
•Only in some bacteria
•Tiny circles of DNA
•Only a few genes
PROKARYOTIC
• No membrane-bound
organelles
• Smaller than eukaryotes
• All unicellular
Reproduction
• Binary Fission
–Chromosome is replicated
–Cell elongates and then
splits in two
–NO MITOSIS NECESSARY
METABOLISM
• Some heterotrophic
• Some autotrophic
–Photosynthesizers
–Chemosynthesizers
•Can get energy from nonorganic compounds:
• ex H2S, NH3
METABOLISM
• Some Aerobic
– Require O2
• Some Anaerobic
– Obligate anaerobes
•Killed by O2
– Facultative anaerobes
•Can exist with or without O2
METABOLISM
• Some secrete TOXINS
–Chemicals that are
poisonous to eukaryotic
cells
–Ex: Tetanus, botulism
COLONIES
• Large clumps of thousands
of bacteria all grown from
one ancestor
• Are genetically identical
• Each species has colonies
with particular
characteristics such as
color, shape, texture
COLONIES
BACTERIAL SHAPES
• Coccus – Round
• Bacillus – Rod-shaped
• Spirillum – Spiral-shaped
• Vibrio – comma-shaped
Vibrio
GROUPINGS
• Micro – individual
• Diplo – pairs
• Strepto – chains
• Staphylo - clusters
Diplococcus
Staphylococcus
Streptococcus
Streptomyces
ENDOSPORES
• Hard-shelled case built
around DNA during harsh
conditions
ENDOSPORES
Gram Staining
• Gram Positive
– Blue
–No capsule
• Gram Negative
–Red
–Capsule
Gram Staining
Gram Staining
• Helps doctor decide
which antibiotic to use
Uses of Bacteria
• Ecosystems
– Decomposers
– Nitrogen fixation
– Oil eaters
• Foods
– Chocolate, soy sauce,
yogurt, vinegar
Uses of Bacteria
• Antibiotics and other
chemicals
• Genetic Engineering
–Plasmids used to
introduce genes
–Insulin, growth hormone
Antibiotics
• Interfere with bacterial
metabolism
• Are not effective against
viruses
• Used to treat bacterial
diseases
• Penicillin, erythromycin,
tetracycline, sulfa drugs,
cephalosporins, etc.
Vaccinations
• Small amount of inactivated virus
or bacteria injected or ingested
• Immune system mounts longlasting response
• Prevents rather than treats
disease
• Measles, mumps, rubella, polio,
chicken pox, meningitis, HPV,
hepatitis, diphtheria, pertussis,
tetanus