Unusual Bacteria

What type of bacteria are Mycobacteria?

Acid-fast bacteria with high mycolic acid content.

Why are Mycobacteria called acid-fast?

Their waxy cell wall contains large amounts of mycolic acid.

What stain is used for Mycobacteria?

Acid-fast stain.

Why doesn't Gram stain work well on Mycobacteria?

Their waxy cell wall resists Gram staining.

Are Mycobacteria fast-growing or slow-growing?

Slow-growing.

What makes Mycobacteria resistant to drying and disinfectants?

Their waxy, mycolic acid-rich cell wall.

How do Mycobacteria evade the immune system?

They survive inside macrophages.

What disease is caused by Mycobacterium tuberculosis?

Tuberculosis (TB).

What disease is caused by Mycobacterium leprae?

Leprosy.

What disease is commonly caused by Mycoplasma?

Walking pneumonia.

What makes Mycoplasma unusual?

It lacks a cell wall.

What unique membrane component does Mycoplasma have?

Sterols.

Why is Mycoplasma naturally resistant to penicillin?

Penicillin targets cell walls, and Mycoplasma has none.

What is the size and shape characteristic of Mycoplasma?

Very small and flexible.

What disease is caused by Rickettsia?

Rocky Mountain spotted fever.

How is Rickettsia transmitted?

By arthropod vectors such as ticks, lice, and fleas.

What type of parasite is Rickettsia?

Obligate intracellular parasite.

Where does Rickettsia replicate?

Inside host cells.

How does Rickettsia spread after replication?

By lysing (bursting) the host cell.

What eye disease can Chlamydia cause?

Trachoma.

What sexually transmitted disease can Chlamydia cause?

Chlamydia.

What is the infectious form of Chlamydia?

Elementary body.

What is the replicative form of Chlamydia?

Reticulate body.

Is Chlamydia an obligate intracellular organism?

Yes.

What do Rickettsia and Chlamydia have in common?

Both are obligate intracellular parasites.

Why do they depend on host cells?

They have reduced genomes and depend on the host for ATP.

How do they spread to new cells?

By bursting out of infected host cells.

What shape are spirochaetes?

Long, thin, spiral-shaped bacteria.

How do spirochaetes move?

Using axial filaments (endoflagella).

What type of motion do spirochaetes use?

Corkscrew motion.

Why is corkscrew motion beneficial?

It allows movement through tissues.

What disease is caused by Borrelia?

Lyme disease.

What disease is caused by Treponema?

Syphilis.

Are Archaea true bacteria?

No.

What kind of organisms are Archaea?

Ancient microorganisms with unique biochemistry.

Do Archaea have peptidoglycan in their cell walls?

No.

What are archaeal cell walls made of instead?

Proteins or polysaccharides.

How are archaeal membranes different?

They contain unique lipids not found in bacteria or eukaryotes.

What do methanogens produce?

Methane gas.

What are thermophiles?

Archaea that live in high temperatures.

What are halophiles?

Archaea that live in high-salt environments.

What are acidophiles?

Archaea that live in acidic environments.

Why are Archaea important in medicine?

They may be a source of new antibiotics.

How can Archaea help the environment?

Through bioremediation of oil spills and toxic waste.

How can methanogens be useful?

They can produce methane for energy.