Prokaryotes

Characteristics

Nucleoid Region

– single circular

chromosome

– plasmids

– mesosome

No membrane-

bound organelles

Ribosomes (70S)

Plasma membrane

Cell wall

– peptidoglycan

Capsule

– glycocalyx

Flagella

Fimbriae

Pili

Asexual Reproduction

Binary Fission: DNA replicates and the

cell divides in two.

Genetic Recombination

Genetic Recombination

Transformation:

– receives fragments of DNA from the

environment

Genetic Recombination

Transduction:

– DNA carried

into a cell

through viruses

Genetic Recombination

Conjugation:

exchange of

DNA

fragments

Classification

Shape

Gram stain reaction

Oxygen requirements

Feeding strategies

Shape

Coccus:

Spherical

Shape

Bacillus:

Rod-

shaped

Shape

Helical:

Spiral-

shaped

Shape

Filamentous

Gram Stain

Gram Stain

Bacteria are stained with a violet

dye (Crystal violet) and iodine

Rinsed in Alcohol

Stained again with a red dye

(Safranin)

Results

– Violet = gram positive

– Red = gram negative

Oxygen Requirements

Obligate aerobes

Obligate anaerobes

Facultative anaerobes

Feeding Strategies

Based on energy and carbon sources

– Photoautotrophs

– Chemoautotrophs

– Photoheterotrophs

– Chemoheterotrophs

Feeding Strategies

Nitrogen Metabolism Nitrogen is needed for proteins and nucleic acids

Nitrogen fixation - convert atmospheric nitrogen into

ammonia

Makes nitrogen available for other organisms

Classification

Phylogeny of Prokaryotes

Domain: Bacteria

Group: Proteobacteria

– Salmonella

bacillus shape, gram

negative, facultative

anaerobe

Diarrhea, nausea –

(chicken and reptiles)

Endotoxin – caused by

membrane

Domain: Bacteria

Group: Proteobacteria

– E. coli

bacillus shape, gram

negative, facultative

anaerobe

Diarrhea

Exotoxin – releases proteins

that cause illness

Domain: Bacteria Group: Chlamydias

– Chlamydia

coccus shape &

gram negative,

oxygen requirement

unknown (related to

O2 in tissues)

Causes blindness

and is the most

common STD in the

US

Domain: Bacteria

Group: Spirochetes

– Treponema

pallidum

Syphilis

Helical, Gram

negative, anaerobic

but oxygen tolerant

Domain: Bacteria

Group: Spirochetes

– Borrelia

burgdorferi

Lyme Disease

Helical, Gram

negative, low O2

requirement

Domain: Bacteria

Group:

Cyanobacteria

– Contains

Chlorophyll A and

phycocyanin

Filamentous, no

stain, aerobic to

facultative

anaerobes

Only organism on

planet that can fix

nitrogen and release

oxygen

pools

Domain: Bacteria Group: Gram-

positive bacteria

– Clostridium

Bacillus shape,

gram positive –

(endospore doesn’t

stain)

Obligate anaerobes

- exotoxins

Causes gangrene,

botulism

Domain: Bacteria

Group: Gram-

positive bacteria

– Bacillus anthracis

Bacillus shape

Gram + (endospore)

Aerobic

Causes pustules,

pneumonia

Domain: Bacteria

Group: Gram-positive

bacteria

– Streptococcus

Coccus shape & gram

positve, anaerobic but

are air tolerant

Intestinal tract –

buttermilk, strep throat

Domain: Bacteria

Group: Gram-

positive bacteria

– Staphylococcus

coccus shape &

gram positive,

facultative anaerobe

Most common type

of food poisoning,

toxic shock

syndrome

Dangerous in

hospitals

Domain: Bacteria: Review

Group:

Proteobacteria

– Salmonella

– E. coli

Group: Chlamydias

– Chlamydia

Group: Spirochetes

– Treponema

– Borrelia

Group:

Cyanobacteria

– Oscillatoria

Group: Gram-

positive bacteria

– Clostridium

– Bacillus anthracis

– Streptococcus

– Staphylococcus

Domain: Archaea

Group: Methanogens

– methane releasing

Group: Halophiles

– lives in high salt

areas

Group: Thermophiles

– lives in extreme

temperatures

Symbiotic Relationships

Mutualism

– both benefit

Commensalism

– one benefits, the other is unharmed

Parasitism

– one benefits at the other’s expense

Bacteria and Disease

Symptoms of disease

– Exotoxins - secreted by bacteria

– Endotoxins - components of the cell wall

Pathogens

– Koch’s Postulates

Koch’s Postulates

Isolate microorganism from dead animal

Grow microorganism in pure culture

Inject microorganism into healthy animal

Microorganisms reproduce in animal

Microorganisms are isolated again

Bioremediation

Sewage Treatment

Oil Spills