Bacteria
Bacteria
Decomposer organisms:
produce enzymes to break
down organic substances
• Microbiologist:
studies microbes
BACTERIA JOBS
 Pathogenic (disease causing)
 Most bacteria are decomposers, they eat
dead things.
 Normal human flora in the digestive tract,
oral cavity, skin, and other areas.
Bacteria
2 Domains: Bacteria & Archea
Kingdoms: Eubacteria & Archaebacteria
Same:
Prokaryotic
Microscopic
Archea is Different:
1) can live in extreme places
2) do NOT have peptidoglycan
3) a little like eukaryotic cells
Archaebacteria Kingdom
 No peptidoglycan in the cell wall.
 Genes resemble Eukaryotic DNA with the
presence of histone proteins.
 Examples are Thermoacidophiles (high
temp or highly acid soils), methanogens
(methane producers), halophiles (saltlovers).
Eubacteria Classification
 Eubacteria are classified by their shape
and by Gram stain.
 Gram stain is a process to determine the
amount of peptidoglycan in the cell wall
and the bacteria is separated by how it
stains.
Bacteria
Common shapes of bacteria
• Coccus = round
Staphlococcus
aureus
Bacteria
Common shapes of bacteria
• Bacillus = rod
Eshrichia
coli
Bacteria
Common shapes of bacteria
• Spirillum = spiral
Leptospira
interrogans
Bacteria
Structure of Bacterial Cell
* nuclear area (DNA)
* ribosomes
* cell membrane
* cell wall
* capsule
* pili (attachment)
* flagellum (mvt)
Bacteria
Bacterial Movement
www.microbiologybytes.com/video/motility.html
1. Flagella
2. Vibrations as H2O molecules
bump into them
Bacteria Reproduction
 Grow to full size and divide in 30
minutes.
 Growth is usually limited to availability of
resources.
 Normally reproduce by simple binary
fission.
 Growth rates vary depending on bacteria.
Bacteria
•
Bacterial Asexual Repro
Chromosome replicates
•
Daughter chromosomes separate
•
Plasma membrane indents
•
Cells separate
Bacteria
Bacterial Nutrition
•
Heterotrophic
* parasitic
* saprophytic
•
Autotrophic
* photosynthetic
* chemosynthetic
Bacteria
Bacterial Photosynthesis
•
bacteriochlorophyll
(purple, red, brown)
•
Hydrogen from hydrogen sulfide
not water
•
Oxygen is not a product
Bacteria
Conditions of Bacterial Growth
•
•
•
•
•
moisture
temp 59oF (15oC) – 95oF (38oC)
neutral pH
food source
light (if photosynthetic)
Bacteria
Bacterial Survival
•
Endospores: protective covering
of nucleoid
•
Reduced metabolism
Bacteria
Genetic Transfer
•
Conjugation: DNA passes from
1 bacteria to another thru a pilus
•
Transformation: bacterial absorb
DNA from environment
•
Transduction: bacteriophage transfers
genetic material
Bacteria Conjugation
Bacteria Transformation
Bacteria Transduction
Bacteria
Mycoplasms
Lack cell walls
Various shapes
Live in specific solute concentrations
cause:
* pneumonia
* arthritis
* urinary tract infections
Bacteria
Rickettsias
Intracellular parasites
Have cell wall
Spherical or rod shaped
causes:
* typhus fever
* Rocky Mtn
spotted fever
Bacteria
Spirochetes
bent or corkscrew shape
some free living
some live in digestive or repro tracts
causes:
lyme disease
Bacteria
Spirochetes
bent or corkscrew shape
some free living
some live in digestive or repro tracts
causes:
lyme disease
syphilis
yaws 
Virus
Dimitri Iwanowski:
worked with TMV
“virus” meaning poison
Dr. Wendell Stanley:
isolated the
TMV virus
Virus Structure
1) Nucleic acid
(DNA or RNA)
2) Protein Coat
H1N1
Virus
Bacteriophage:
virus that infects bacteria
Bacteriophage picture
Virus
Lytic Cycle & Lysogenic Cycles
Virulent virus:
reproduces & injures cells immediately
Latent virus:
Lytic and Lysogenic cycle
Virulent virus:
reproduces & injures cells immediately
AIDS Virus
budding from
a human
blood cell
Latent virus:
remains inactive for long periods of time
Latent virus:
Diseases & Disorders
Infectious diseases:
caused by a pathogen
incubation period:
time between contracting the disease
& coming down with symptoms
Communicable Diseases:
can spread from person to person
* droplets
* contact
* contamination
* wound infection
* insect vectors
(mechanically or by bites)
* immune carriers
Mary Malone
Typhoid Mary
Man With TB Locked Up To Protect Public
Tuberculosis Patient
Confined To Arizona Jail Cell
Major viral diseases
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Ebola
Hepatitis A, B, C, D
Herpes
Mononucleosis
Mumps
SARS
Warts
Yellow Fever
Major viral disease
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HIV
Chicken pox
Cold
Flu
Measles
Polio
Rabies
West Nile
How do you stop viruses?
Either by vaccines or antiviral drugs
 Vaccinations
inactivated vaccines – dead virus
attenuated vaccine – altered live virus
How do you stop viruses?
Antiviral Drugs
interferons – stop protein production for
viral replication
Protease Inhibitors – stop protein
synthesis
Fusion inhibitors – blocks virus from
entering cell
Pathogens effects:
1. Tissue destruction
2. Toxin formation
exotoxins
endotoxins
ex: tetanus & botulism
ex: bubonic plague
Structural Defenses: 1st line of defense
* Skin &Mucous membranes
* Tears (lysozyme)
Cellular Defenses: 2nd line of defense
phagocytic cells
inflammation
lymphatic system
fever
Specific Defenses: 3rd line of defense
immune system
antibodies
Defense against Diseases
Bacteriocidal chemicals:
kill bacteria
examples: antibodies, antibiotics like
penicillin & streptomycin
Defense against Diseases
Antibiotics work by:
1) interfering with bacterial metabolism
2) disrupting cell wall
3) interfering with protein synthesis
4) inhibiting RNA synthesis
Defense against Diseases
Bacteriostatic chemicals:
prevent multiplication of bacteria
examples: sulfa drugs
Viroids
Infectious strand of circular RNA
Prions
Abnormal form of a protein
Causes mad cow disease & scrapie
Koch’s Postulates
Steps to identify pathogens:
1.Seen only in sick people
2.Grown in lab
3.Injected into healthy subject and see if
they get the disease (experiment with
mice)
4.Compare the pathogens from the one
found and the one injected to see if they
are the same