Chapter 11 [Part 3/3] - Characterizing and Classifying Prokaryotes

Gram-negative bacteria

Bacteria that have a thin peptidoglycan cell wall and a secondary membrane but lack a thick peptidoglycan wall.

Peptidoglycan

A polymer that composes the cell wall of many bacteria, providing structural support.

Lipid A

A component of lipopolysaccharides (LPS) that can elicit strong immune responses in humans.

Proteobacteria

A major phylum of gram-negative bacteria classified into six classes: Alpha, Beta, Gamma, Delta, Epsilon, and Zeta.

Alpha Proteobacteria

A class of proteobacteria that are primarily aerobic, capable of nitrogen fixation, and can form unique structures called prostheca.

Rickettsia

A genus of gram-negative bacteria that are obligate intracellular parasites, known to cause diseases like typhus.

Brucella

A genus of gram-negative bacteria that can cause brucellosis, characterized by symptoms such as fatigue and fever.

Agrobacterium

A genus of bacteria known for its ability to transfer DNA to plant cells, causing tumor-like growths.

Beta Proteobacteria

A class of proteobacteria that thrive in varied environments, including the presence of low nutrients.

Neisseria gonorrhoeae

A pathogenic species of Neisseria responsible for gonorrhea, a sexually transmitted disease.

Bordetella

A genus of bacteria known for causing whooping cough.

Gamma Proteobacteria

The largest and most diverse class of proteobacteria, encompassing various intracellular pathogens and opportunistic pathogens.

Pseudomonas

A genus of bacteria known for its metabolic versatility, including the ability to degrade complex organic compounds.

Delta Proteobacteria

A class of proteobacteria that includes genera known for their ability to recycle sulfur and some pathogenic bacteria.

Myxobacteria

A group of bacteria known for their social behavior, including cell differentiation and coordinated movements.

Epsilon Proteobacteria

A class of proteobacteria that includes pathogens like Campylobacter and Helicobacter, associated with gastrointestinal diseases.

Zeta Proteobacteria

A recently classified class of proteobacteria, primarily marine and autotrophic, with few identified species.

Biofilms

Aggregates of microorganisms that adhere to surfaces and are encased in a self-produced matrix.

Flocs

Aggregates of bacteria and organic matter formed during sewage treatment, which can aid or hinder water purification.