Chapter 4- Prokaryotic Diversity

What are the two domains of prokaryotes?

Bacteria and Archaea

What does it mean that prokaryotes are "ubiquitous"?

They are found almost everywhere on Earth.

Name four habitats where prokaryotes can live.

Hot springs, ice caps, deep ocean, and skin/mucosal surfaces.

Why can prokaryotes survive in so many different environments?

They are highly adaptable and resilient, and many can switch their metabolism or respiration methods.

Why is prokaryotic diversity important?

It helps maintain ecosystem stability, carbon fixation, nitrogen fixation, and environmental cleanup.

What are some harmful effects of prokaryotes?

They can cause human diseases and contribute to climate change.

What is a symbiotic association?

A close relationship between different organisms where they live together.

Give an example of a beneficial symbiotic relationship involving prokaryotes.

Gut bacteria help with nutrient metabolism.

How do skin bacteria benefit humans?

They provide antimicrobial defense by preventing harmful microbes from growing.

How can skin cells benefit prokaryotes?

Skin cells serve as a food source.

Why do some bacteria form spores in soil?

To survive harsh environmental conditions.

Name two diseases caused by prokaryotes.

Tuberculosis and leprosy.

What is Mutualism?

Both A and B beneffited

What is Amensalism?

One is harmed, One is unaffected

What is Commensalism?

One is benefited, One is unaffected

What is Neutralism?

Both A and B unaffected.

What is Parasitism?

One is benefited, One is harmed.

What is a polymicrobial community?

A community made up of multiple species of microorganisms living together.

What is competing community?

They compete for scarce resources.

What is cooperative community?

Microorganisms interact, share resources.

What is a microbiome?

The community of prokaryotes and eukaryotic microbes living in a particular environment.

What is the difference between resident and transient microbiota?

Resident microbiota normally live in a location long-term; transient microbiota are temporary.

Do microbiomes differ between body sites and organisms?

Yes, each site and organism has a unique microbiome.

What factors influence the microbiome?

Environment, diet, age, health, lifestyle, antibiotics, and other factors.

Do prokaryotes reproduce sexually?

No

Why is classifying prokaryotes difficult?

They have few distinctive morphological features and do not reproduce sexually.

What methods are used together to classify prokaryotes?

Molecular analysis, biochemical tests, microscopy, and nucleotide sequence comparisons.

What staining method is commonly used to classify bacteria?

Gram staining

What are the major Gram-negative bacterial phyla?

Proteobacteria, Spirochetes, CFB group, and Phototrophic bacteria.

What are the two major Gram-positive bacterial phyla?

High G+C (Actinobacteria) and Low G+C (Firmicutes).

Which Gram-positive group has high G+C content?

Actinobacteria

Which Gram-positive group has low G+C content?

Firmicutes

What is the prominent genera of Alphaproteobacteria?

Rickettsia

What does "obligate intracellular" mean in Rickettsia?

The bacteria must live inside a host cell to be metabolically active and reproduce.

What are the 3 species of Rickettsia ?

R. rickettsii

R. prowazakii

R. typhi

What disease does Rickettsia rickettsii cause?

Rocky Mountain spotted fever.

What disease does Rickettsia prowazekii cause?

Epidemic typhus (more severe).

What disease does Rickettsia typhi cause?

Endemic (murine) typhus (less severe).

How is Rickettsia commonly transmitted?

By ticks.

What is the prominent genera of Betaproteobacteria?

Bordetella & Neisseria

Which bacterium causes whooping cough (pertussis)?

Bordetella pertussis.

How does Bordetella pertussis damage the lungs?

It produces toxins that paralyze the cilia.

Which bacterium causes gonorrhea STD?

Neisseria gonorrhoeae.

Which bacterium causes bacterial meningitis?

Neisseria meningitidis.

What is the shape of Neisseria?

Coffee bean-shaped diplococci (pairs).

What special growth requirements does Neisseria have?

Moisture, high CO₂, and chocolate agar.

Which class of Proteobacteria is the largest and most diverse?

Gammaproteobacteria

What is the prominent genera of Gammaproteobacteria?

Pseudomonas, Haemophilus, Vibrio, Legionella, Enterobacter family

Which bacterium commonly infects burn wounds?

Pseudomonas aeruginosa.

What other infections are caused by Pseudomonas aeruginosa?

Urinary tract infections and respiratory infections.

Why is Pseudomonas aeruginosa difficult to treat?

It is often antibiotic resistant.

Which pigments does Pseudomonas produce?

Blue and yellow pigments (green appearance).

Does Haemophilus influenzae cause influenza?

No. It causes upper and lower respiratory infections.

Which bacterium causes cholera?

Vibrio cholerae.

Where is Vibrio commonly found?

Alkaline aquatic environments such as ocean ports and lagoons.

How is cholera commonly spread?

Contaminated water.

Vibrio spp. is responsible for?

Gastrointestinal disease, cellulitis, blood-borne infections

Which bacterium causes Legionnaires' disease?

Legionella pneumophila.

Where is Legionella commonly found?

Contaminated water systems.

Name two important members of the Enterobacter family.

Escherichia coli and Salmonella. spp

What are coliforms?

Bacteria similar to E. coli that completely ferment lactose.

What are noncoliforms?

Bacteria that incompletely ferment lactose or do not ferment lactose.

Are most strains of E. coli harmful?

No. Most are beneficial (mutualistic).

What toxin can pathogenic E. coli produce?

Shiga toxin.

What disease does Salmonella commonly cause?

Salmonellosis

Which Salmonella serotype causes typhoid fever?

Salmonella enterica (serovar typhi.)

Which is the proteobacteria relatively small class?

Deltaproteobacteria

Which Deltaproteobacteria parasitizes other bacteria-?

Bdellovibrio app

Which species is associated with periodontal disease?

Desulfovibrio orale.

Which Deltaproteobacteria are called slime bacteria?

Myxobacterium

Deltaproteobacteria sulfate reducing bacteria ?

Few are pathogenic

Which is the proteobacteria smallest class?

Epsilonproteobacteria

Are Epsilonproteobacteria microaerophilic?

Yes, Microaerophilic

What are Epsilonproteobacteria prominent genera?

Campylobacter & Helicobacter

Which Campylobacter infection is commonly associated with food poisoning

Campylobacter jejuni.

Which bacterium is associated with stomach ulcers?

Helicobacter pylori.

Which bacterium is associated with stomach cancer?

Helicobacter pylori.

Is Helicobacter always harmful?

No. It is often beneficial but can cause ulcers and stomach cancer in susceptible people.

What are the 3 Gram-Negative nonproteobacteria?

Chlamydia, Spirochetes, CFB group

Which bacterium causes lymphogranuloma venereum (STD)?

Chlamydia trachomatis.

Is Chlamydia trachomatis an obligate intracellular pathogen?

Yes, needs host to survive and reproduce

What are the two life stages of Chlamydia?

Inactive elementary bodies and active reticulate bodies.

Which form of Chlamydia is infectious?

Elementary body.

Which form of Chlamydia is metabolically active and reproduces?

Reticulate body.

What are spirochetes?

Extremely thin, Gram-negative-like bacteria with spiral shapes and axial filaments for movement.

Why are spirochetes difficult to stain?

They are extremely thin and are best viewed using darkfield microscopy.

Which bacterium causes syphilis?

Treponema pallidum pallidum.

Which bacterium causes Lyme disease?

Borrelia burgdorferi. (ticks)

The CFG group stands for?

Cytophaga, Fusobacteria, Bacteroides

Which genus is known for gliding motility?

Cytophaga spp,

What are the mechanisms of cytophaga?

Mostly unknownn

Which CFB genus commonly inhabits the mouth?

Fusobacterium spp.

What diseases can Fusobacterium cause?

Periodontitis, oral ulcers, and other oral diseases.

Which genus makes up about 30% of the human gut microbiome?

Bacteroides.

What has been associated with lower levels of Bacteroides?

Obesity

How are phototrophic bacteria grouped?

By function rather than taxonomy.

What is the main energy source for phototrophic bacteria?

Sunlight/Photosynthesis

What are the major groups of phototrophic bacteria?

Purple bacteria, green bacteria, and cyanobacteria.

What pigments do purple and green bacteria contain?

Bacteriochlorophylls

Which phototrophic bacteria contain chlorophyll?

Cyanobacteria.