Bacteria

Kingdom Eubacteria (True Bacteria)
Bacteria are located everywhere – air, water, land, and living organisms including people.
General Characteristics:
1. All are unicellular (one-celled structural level)
2. All are prokaryotic - cells that lack nucleus (no nuclear envelope) (PRO = NO nucleus)
3. All have cell walls – NO cellulose in cell walls
4. Can live in both aerobic (with O2) and anaerobic (without O2) environments

5. Bacteria are much larger in size than viruses.

6. Bacteria usually have one of three different cell shapes:
Coccus
(Sphere-shaped)
Ex: Streptococcus
Bacilli
(rod-shaped)
Ex: Lactobacillus
Spirillum
(Spiral-shaped)
Ex: Spirillium

coccus
bacillus
spirillum
coccus
spirillum
bacillus
What shape?

Example: E. coli

Causes Disease by:
1. Destroying cells of infected organisms by breaking the cells down for food.

Releases toxins (poisons) which destroy cells of infected organism.
Must have access to new hosts to spread.

Different Hosts

D. Importance:
1. Beneficial
a. breakdown dead matter to recycle nutrients into ecosystem - decomposers

Example: Compost piles need microorganisms (ex. bacteria) to decompose (breakdown) matter.

b. dairy industry - bacteria in 2:08 minute video
yogurt, sour cream and cheese

c. Oil spills - bacteria can digest small oil spills

d. Genetic
engineering—
Recombinant/synthetic DNA (Ex: Insulin)

e. symbiotic relationship - E. coli and our
intestines-both organisms benefit
Example: E. coli in intestines helps us digest food and make vitamins (such as Vitamin K and B-complex) In return, human intestines provide food and shelter for bacteria.
(This strain of E. coli is different from the E. coli strain that causes food poisoning.)

3:07 minute video

Harmful :
human diseases –
strep throat, tuberculosis,
tooth decay and bad
breath, anthrax, plague,
tetanus, food poisoning

3:15 minute video

b. food spoilage and poisoning – caused by
Salmonella and Staphylococcus
c. Treated with antibiotics – Some bacteria are able
to survive in presence of antibiotics that kill
other bacteria – antibiotic resistant bacteria
Note: This is why doctors tell you to take the entire amount of medicine given even if you start to feel better because if not, bacteria will have the chance to evolve and become antibiotic resistant.

Kingdom Archaebacteria
First known prokaryotes-
Archaebacteria (archae=ancient)
b. Live in very harsh environments
(known as extremophiles)– high salt content, hot temperatures, acidic or alkaline environments

3:12 minute video