Bacteria
I.
General Characteristics
A.
Single-celled; no nucleus or complex organelles

What do we call this type of organism?
B.
Earliest known life forms
C.
Live almost everywhere on the planet
(air, water, soil, on animals, etc.)
D.
Smallest and simplest living organisms
Needle Tip
II. Bacterial Structure
Some bacteria (like the one that causes pneumonia)
have a sticky coating around the cell wall called a
capsule or slime layer
A.
1.
Protects the bacterium and helps it stick to surfaces
B.
Many bacteria have a whip-like tail called a
flagellum that helps it move and/or pili that
allow it to attach to things
flagellum
pili
C.
Bacterial cells contains cytoplasm surrounded
by a cell membrane and a cell wall; but no
membrane-bound organelles-just ribosomes
D.
1.
Most of the genetic material is found in the
nucleoid region (loosely coiled DNA)
Some bacteria also have a small, independent
circular piece of DNA called a plasmid
DRAW
1. Cell membrane
2. Ribosome
6. Cell wall
3. Nucleoid
region
4. Cytoplasm
5. Pili (short flagella)
III. Classification
Bacteria are placed into two kingdoms:
A.
1.
2.
Kingdom Archaebacteria
a.
Oldest "ancient" bacteria
b.
Found in harsh environments
Kingdom Eubacteria
a.
Largest and most varied bacteria group
b.
"True" bacteria (germs)
B.
Grouped according to their shape and
arrangement:
1. Coccus (i) = Spherical shaped cells
a. single coccus
b. diplococci (pairs)
c. Streptococci (chains)
d. Staphylococci (clusters)
Streptococci
fecal
necrotizing
fascitis
Staphylococci
2. Bacillus (i) = Rod shaped cells
a. Single bacilli
b. Diplobacilli
c. Streptobacilli
3.
Spirillium = Spiral shaped
3 Basic Shapes
C.
Grouped according to how they obtain food
and use energy
1.
Autotrophic (______________________________)
a) Photosynthesis (Ex: Cyanobacteria "blue-green"
bacteria)
b) Chemosynthesis (Ex: extremophiles)
2. Heterotrophic
(___________________________)
a) Saprophytes (decomposers)
i. Live on and eat dead things using extracellular
digestion
ii. Secrete enzymes that digest their food
iii. They absorb the food back into their cells by
diffusion
iv. This is why food gets mushy when it rots
Rotting Watermelon Movie
b)
Symbiotes - two organisms living closely together
i. Parasitism
ii. Commensalism
iii. Mutualism
IV. Circulation, Excretion and Respiration
A.
What do these words mean?
B.
By diffusion
C.
Obligate aerobes
1. Must have oxygen to live
e.g. Mycobacterium tuberculosis
D. Obligate anaerobes
1. Can’t live in the presence of oxygen
e.g. Clostridium botulinum
 spores can be found in honey
E. Facultative anaerobes
1. Can grow with or without O2 but do better without O2
e.g. Escherichia coli
V. Optimal Growth Requirements
A.
Warmth; 25-37 °C
B.
Dark
C. Moisture
D. Food

Where do we normally find these
conditions?
VI. Reproduction
A. Asexual
1. Binary fission - splitting into two equal cells
B. Sexual reproduction
1. Conjugation - exchange of plasmids
a) After plasmid is exchanged one bacterium
usually dies.
VII. Beneficial effects of bacteria
A.
Decompose organic material
B.
Used to make antibiotics How?
C.
Necessary for human survival
1.
Make vitamin K in intestines and farting (methane gas)!
D.
Nitrogen fixation in N cycle (make N usable by plants)
E.
Bioremediation
1.
Break down wastes and pollutants (oil, wastewater,
toxic spills)
Food production
F.
1.
Ex: yogurt, cheeses, vinegar, buttermilk, sauerkraut,
pickles, olives, etc.
VIII. Harmful Effects of Bacteria
A.
Pathogenic (cause diseases)
By directly damaging cells as they are digested for food.
2. Indirectly damaging cells by releasing toxins which
damage host.
3. Some bacteria produce thick-walled structures called
endospores when conditions are unfavorable.
a) Remain dormant for years, then resume growth of
normal bacteria that produces toxins (botulism spores in
honey)
4. Ex: Strep throat, botulism, tuberculosis, gonorrhea,
typhoid fever, bubonic plague, diphtheria, cholera, tetanus
etc.
1.
B. Other problems caused by bacteria
1. Food spoilage (many species)
2. Food poisoning Salmonella sp.
3. Disorders like boils, pimples, pneumonia,
and some forms of arthritis
IX. Treatment of bacterial diseases
A.
1.
Pasteurization (heating to temperatures that kill
bacteria) and sterilization (UV light & alcohol)
Help prevent the spread of disease
B.
Vaccines
C.
Antibiotics (made from fungi or other bacteria)
D.
Problems with Antibiotics
1.
Antibiotic resistance.
2.
Kills off good bacteria as well as bad.
3.
Inhibits body's natural immunity.