Major Groups & Unusual Bacteria

What are the three major domains?

Bacteria, Archaea, and Eukarya.

What is the major cell wall characteristic of Proteobacteria?

Gram-negative cell walls.

What is the major characteristic of Firmicutes?

They are mainly Gram-positive with low G+C content.

What is the major characteristic of Actinobacteria?

They are Gram-positive with high G+C content.

What are cyanobacteria?

Gram-negative photosynthetic bacteria that produce oxygen.

What type of photosynthesis do cyanobacteria perform?

Oxygenic photosynthesis.

Why are cyanobacteria important to the atmosphere?

They are a major source of free oxygen.

What pigment do green and purple sulfur bacteria contain?

Bacteriochlorophyll.

Do green and purple sulfur bacteria release oxygen during photosynthesis?

No.

What type of photosynthesis do green and purple sulfur bacteria perform?

Anoxygenic photosynthesis.

What are Rickettsias?

Very tiny Gram-negative bacteria that are obligate intracellular parasites.

What disease is caused by Rickettsia rickettsii?

Rocky Mountain spotted fever.

What are Chlamydias?

Tiny obligate intracellular parasites.

What are elementary bodies?

Rugged Chlamydia cells that can survive outside the host.

What disease can Chlamydia trachomatis cause?

Severe eye infection and sexually transmitted disease.

What can Chlamydia pneumoniae cause?

Lung infections.

What distinguishes Archaea from Bacteria?

Archaea have unique genetic sequences, membrane lipids, and cell walls.

Where do many Archaea live?

Extreme environments.

What are examples of archaeal extremophiles?

Methane producers, hyperthermophiles, extreme halophiles, and sulfur reducers.