BACTERIA

Kingdom Eubacteria

Kingdom Archaebacteria

PROKARYOTES

Bacteria classification

• Domain Bacteria: Kingdom Eubacteria (“true”)

• Domain Archea: Kingdom Archaebacteria (“ancient”)

• All bacteria were previously combined under Kingdom Monera

* ALL bacteria are prokaryotic

Kingdom: Archaebacteria “ancient”

• Autotrophic

• Cell walls with NO peptidoglycan

• Live in extreme environments

1. Methanogens- no oxygen, make

methane gas

2. Thermophiles- very hot water

3. Halophiles- very salty conditions, 10x saltier than ocean water

Archaea in San Francisco Bay area – extremely high salinity.

What kind of archaea are these?

Kingdom: Eubacteria “true”

• Largest and most diverse of the bacterial kingdoms

• Found everywhere

• Most are HETEROTROPHIC

• Cell walls are present with peptidoglycan

• Many have flagella that aid in movement

How do Bacteria Reproduce?

• Most reproduce asexually through binary fission. ( Dividing in half; identical offspring)

• Some reproduce sexually by conjugation connecting at their pili. (cell to cell contact; new combination of genes)

Asexual reproduction: Rod-shaped bacteria dividing by binary fission

Pili on a bacillus bacterium

Sexual reproduction: Conjugation in bacteria

endospores • Thick wall

• Resistant to heat, dryness, etc

• May survive for years in harsh conditions

• When conditions are favorable, the bacteria will grow from the spore

• Example: ANTRHAX

How are Bacteria Classified?

• cell shape

• cell wall –Archaea and the Bacteria

–Gram+ bacteria and Gram- bacteria

• respiration

• nutrition

Three different shapes:

– Coccus (spheres)

– Bacillus (rods)

– Spirillum (spirals)

Two different arrangements:

– Strepto (chains)

– Staphylo (clusters)

Bacterial Shapes

coccus

spirillum

bacillus

Cell Wall: Gram+ vs. and Gram-

Color

Purple

Red

Amount of peptidoglycan

More

Less

Toxicity

Less

More

Antibiotic effective against?

Most of the time

Not always

Feature Gram + Gram -

Gram +

Gram –

the lipid layer on the outside makes it hard for antibiotics to work on G-

Peptidoglycan – the tan rods in the diagram; lots in Gram +, little in Gram -

Nutrition Types • AUTOTROPHS

– Photosynthetic—use pigments to capture light energy to convert to chemical energy ex. cyanobacteria

– Chemosynthetic—use inorganic molecules or organic molecules to make amino acidsproteins; live in soil and nitrify ammonia ex. sulfur bacteria & methanogens; nitrifying bacteria (Nitrobacter spp.)

• HETEROTROPHS

– Principal decomposers (along with fungi)

– Many produce antibiotics (ex. Streptomyces)

– Some fix nitrogen (ex. Rhizobium)

Diseases caused by Bacteria:

* Tuberculosis

* Anthrax

* Lyme disease

* E. coli

* Bubonic plague

*Typhoid fever *Cholera

*Strep throat *Dental cavities

*diphtheria *pneumonia

Yellow bacillus bacteria in the lining of the human nose. This species causes pneumonia.

Beneficial Bacteria: There are some bacteria you’ve just got to love!

* Bacteria is used to make certain foods like cheese and yogurt.

* To manufacture plastics and many pharmaceuticals.

* Digests cellulose in animals

* Sewage treatment plants

* Medicines like insulin

Mutualistic bacteria: the fish provides the bioluminescent bacteria under its eye with organic materials, the fish uses its living flashlight to lure prey and to signal potential mates.

Questions to Ponder

• Why are bacteria important organisms in the ecosystem?

• What are the shapes and arrangements of bacteria and how can these be used in classification?

• Describe bacterial diseases including cause, symptoms, and transmission.

• In what ways are bacterial beneficial to us? Explain.

How do we know that those little bitty things under the microscope aren’t all the same “stuff”?

How do we know that the Archaea are more closely related to the Eukarya?