Download Domain Bacteria Kingdom Eubacteria

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. Smallest and simplest living organisms
D. Size 20 - 200 microns in diameter and 50
– 1,000 microns long
E. Few hundred genes
Needle Tip
II. Bacterial Structure
A.
All bacteria have an outer cell wall made out of
glycoproteins or lipoprotein
II. Bacterial Structure (cont)
B.
Some bacteria have a sticky envelope around
the cell wall called a capsule or slime layer
II. Bacterial Structure (cont)
C.
Very simple internal organization
1) Cytoplasm with very few organelles
2) Nucleoid region (loosely coiled DNA)
1. Cell membrane
2. Ribosome
3. Nucleoid
6. Cell wall
4. Cytoplasm
5. Pili (short flagella)
III. Classification
Bacteria are placed into two major
kingdoms:
A.
1.
Kingdom Archaebacteria - oldest bacteria,
found in harsh environments
2.
Kingdom Eubacteria -True bacteria, the
largest group.
Bacteria Overview Movie
B.
Grouped according to their shape and
arrangement:
1) Coccus (i) = Spherical shaped cells
a) single cocci
b) diplococci (pairs)
c) Streptococci (chains)
d) Staphylococci (clusters)
III. Classification (cont)
Staphylococci (clusters)
III. Classification (cont)
2) Bacillus (i) = Rod
a) single bacilli
b) Diplobacilli
c) Streptobacilli
shaped cells
III. Classification (cont)
Streptobacilli
III. Classification (cont)
3.
Spirillium = spiral shaped
III. Classification (cont)
III. Classification (cont)
C.
Bacteria can also be grouped according to
their living arrangements
Saprophytes - live on dead things
(decomposers)
2. Symbiotes - Two organisms living and
depending on each other
a) Parasitic
b) Commensulistic
c) Mutualistic
1.
IV. Optimal Growth Requirements
A. Warmth; 25-37 °C
B.
Dark
C.
Moisture
D. Food

Where can we normally find these conditions?
V.
Movement
A. Many forms
have flagella for
movement
B. Some bacteria
have pili, which
allow them to
attach to other
things
VI. Feeding and digestion
A. Autotrophic
 What does this mean?
1) Photosynthetic (e.g. cyanobacteria or blue-green
algae)
VI. Feeding and digestion
2) Chemosynthetic (e.g. methanogens or
halophiles)
VI. Feeding and digestion
B. Heterotrophic
 What does this mean?
C. Extracellular digestion
1. Secret enzymes
2. Digest their food
3. They absorb the food back into their cells by
diffusion
 Why does food get mushy when it rots?
 Rotting Watermelon Movie
VII. Circulation, Excretion and
Respiration
A. By diffusion
B. Obligate aerobes
1. Must have oxygen to live
e.g. Mycobacterium tuberculosis
VII. Circulation, Excretion and
Respiration
C. Obligate anaerobes
1. Can not live in the
presence of
oxygen
e.g. Clostridium
botulinum
 spores can be
found in honey
VII. Circulation, Excretion and
Respiration
D. Facultative anaerobes
1. Can grow with or without O2 but do better
without O2 e.g. Escherichia coli
VIII.Reproduction
A. Asexual
1. Binary fission - splitting into two equal cells
B. Sexual reproduction
1. Conjugation-exchange of plasmids
a) plasmids are independent circular pieces of
DNA in bacteria.
b) after plasmid is exchanged one bacterium
usually dies.
IX.
Harmful Effects of Bacteria
A. Pathogenic (cause diseases)
1. By directly damaging cells as they digest cells
for food.
2. Or by indirectly damaging cells by releasing
toxins which damage hosts.
3. They also trigger body's immune response, i.e.
fever or inflammation.
4. Examples: botulism, tuberculosis, gonorrhea,
typhoid fever, bubonic plague, diphtheria,
cholera, tetanus etc.
IX. Harmful Effects of Bacteria
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.
X.
Treatment of bacterial diseases
A. Antibiotics are usually made from fungi or other
bacteria. why?
1.
Examples: Penicillin, Streptomycin, tetracycline, and
sulfa drugs.
B. Problems with Antibiotics
1.
Antibiotic resistance.
2.
Kills off good bacteria as well as bad.
3.
Inhibits body's natural immunity.
C. Pasteurization and sterilization (UV & alcohol)
help prevent the spread of disease.
XI.
Beneficial effects of bacteria
A. Decomposition of organic material
B. Nitrogen fixation in some plants (legumes)
C. Used to make antibiotics
D. Food production: e.g. Yogurt, Cottage cheese,
Blue cheese,Vinegar
E. Used as a tool in genetic engineering
F.
Tanning leather
G. Curing tobacco
H. Bioleaching-extracting minerals from ore
deposits