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 O
2 anaerobic (without O
2
) and
) environments

General Characteristics
•Bacteria are prokaryotic organisms (Kingdom:Monera), without cell defined organelles like mitochondria,Golgi bodies,Endoplasmic reticulum.,etc
•Microscopic,unicellular,they may occur singly or aggregations to form colonies.
•They posses rigid cell wall. Cell wall is made up ofpeptidoglycan
(Mureins) and Lipo polysaccharides.
•Absence of well defined nucleus.i.e., DNA is not enclosed in a nuclear membrane.
•Ribosomes are scattered in the cytoplasmic matrix and are of 70S type.
•The plasma membrane is invaginated to form mesosomes.
•Most of the bacteria are heterotrophic.Some bacteria are autotrophic, possesbacteriochlorophyll, which is not in plastids.Instead it is found scattered.
•Motile bacteria posses one or more flagella.
•The common method of multiplication is binary fission.
•True sexual reproduction is lacking,but genetic recombination occurs by conjugation ,transformation and transduction

5. Bacteria are much larger in size than viruses.

Ex: Streptococcus Ex: Lactobacillus Ex: Spirillium

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

General Characteristics of Prokaryotic Organisms
• Prokaryotes
– Most diverse group of organisms
– Habitats
• From Antarctic glaciers to thermal hot springs
• From colons of animals to cytoplasm of other prokaryotes
• From distilled water to supersaturated brine
• From disinfectant solutions to basalt rocks
– Only a few capable of colonizing humans and causing disease

General Characteristics of Prokaryotic Organisms
[INSERT FIGURE 11.1]

General Characteristics of Prokaryotic Organisms
• Reproduction of Prokaryotic Cells
– All reproduce asexually
– Three main methods
• Binary fission (most common)
• Snapping division
• Budding

General Characteristics of Prokaryotic Organisms
[INSERT FIGURE 11.2]

General Characteristics of Prokaryotic Organisms
[INSERT FIGURE 11.5]

General Characteristics of Prokaryotic Organisms
• Arrangement of Prokaryotic Cells
– Result from two aspects of division during binary fission
• Planes in which cells divide
• Separation of daughter cells

General Characteristics of Prokaryotic Organisms

General Characteristics of Prokaryotic Organisms

General Characteristics of Prokaryotic Organisms
• Endospores
– Produced by Gram-positive
Clostridium
Bacillus and
– Each vegetative cell transforms into one endospore
– Each endospore germinates to form one vegetative cell
– Constitute a defensive strategy against hostile or unfavorable conditions
– Serious concern to food processors, health care professionals, and governments

General Characteristics of Prokaryotic Organisms
[INSERT FIGURE 11.8]

• Currently based on genetic relatedness of rRNA sequences
• Three domains
– Archaea
– Bacteria
– Eukarya

Survey of Archaea
• Common features
– Lack peptidoglycan
– Cell membrane lipids have branched hydrocarbon chains
– AUG codon codes for methionine
• Classified in three phyla: Crenarchaeota, Euryarchaeota,
Korarchaeota
• Reproduce by binary fission, budding, or fragmentation
• Most are cocci, bacilli, or spiral forms; pleomorphic forms exist
• Not known to cause disease

Survey of Archaea
• Extremophiles
– Require extreme conditions of temperature, pH, and/or salinity to survive
– Prominent members are thermophiles and halophiles

Survey of Archaea
• Extremophiles
– Thermophiles
• DNA, RNA, cytoplasmic membranes, and proteins do not function properly below 45ºC
• Hyperthermophiles – require temperatures over 80ºC

Survey of Archaea
[INSERT FIGURE 11.11]

Survey of Archaea
• Extremophiles
– Halophiles
• Inhabit extremely saline habitats
• Depend on greater than 9% NaCl to maintain integrity of cell walls
• Many contain red or orange pigments; require protection from visible and UV light
• Most studied – Halobacterium salinarium

Survey of Archaea
[INSERT FIGURE 11.12]

Survey of Archaea
• Methanogens
– Largest group of archaea
– Convert carbon dioxide, hydrogen gas, and organic acids to methane gas
– Convert organic wastes in pond, lake, and ocean sediments to methane
– Some live in colons of animals; one of primary sources of environmental methane
– Have produced ~10 trillion tons of methane that is buried in mud on ocean floor

Survey of Bacteria
• Deeply Branching and Phototrophic
Bacteria
– Deeply branching bacteria
• Scientists believe these organisms are similar to earliest bacteria
• Autotrophic
•
•
• Live in habitats similar to those scientists think existed on early Earth
Aquifex – considered to represent earliest branch of bacteria
Deinococcus – has outer membrane similar to
Gram-negatives, but stains Gram-positive

Survey of Bacteria
• Deeply Branching and Phototrophic
Bacteria
– Phototrophic bacteria
• Phototrophs that contain photosynthetic lamellae; autotrophic
• Divided into five groups based on pigments and source of electrons for photosynthesis
– Blue-green bacteria (cyanobacteria)
– Green sulfur bacteria
– Green nonsulfur bacteria
– Purple sulfur bacteria
– Purple nonsulfur bacteria

Survey of Bacteria
• Low G+C Gram-Positive Bacteria
– Mycoplasmas
• Facultative or obligate anaerobes
• Lack cell walls
• Smallest free-living cells

Survey of Bacteria
[INSERT FIGURE 11.15]

Survey of Bacteria
• Gram-Negative Proteobacteria
– Alphaproteobacteria
• Nitrogen fixers
–
–
Azospirillum
Rhizobium
• Nitrifying bacteria
– Nitrobacter
• Purple nonsulfur phototrophs

Survey of Bacteria

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

2:08 minute video

c. Oil spills - bacteria can digest small oil spills

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

e. symbiotic relationship -
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.)

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

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

c. Live in intestines of animals, especially cows and other grazing animals – methanogens
Produce methane gas – greatly affects our
atmosphere by combining with O
2 to make CO photosynthesis
2 for methanogenic archaebacteria