| A | B |
|---|
| Eubacteria | Members of the kingdom Eubacteria. |
| Archaebacteria | These bacteria are more ancient than the eubacteria and belong to the kingdom Archaebacteria. |
| Peptidoglycan | A protein-carbohydrate compund found in the cell walls of eubacteria. |
| Methanogens | A broad phylogenetic group of archaebacteria, named for their unique way of harvesting energy by converting hydrogen gas and carbon dioxide into methane gas. |
| Extreme halophiles | Salt-loving archaebacteria. They live in environments with very high salt contents. |
| Thermoacidophiles | A group of archaebacteria that live in extremely acidic environments that have extremely high temperatures. |
| Bacilli | Rod-shaped eubacteria. |
| Cocci | Spherical eubacteria. |
| Spirilla | Spiral eubacteria. |
| Streptococci | Long chains of cocci. |
| Staphylococci | Grape-like clusters of cocci. |
| Gram stain | A test performed with dyes to identify bacteria. |
| Gram-positive | Appear purple after the test. |
| Gram-negative | Appear pink after the test. |
| Capsule | An outer covering found in many bacteria. |
| Glycocalyx | When a capsule consists of a sticky coat of sugars. |
| Pili | Short, hairlike protein structures found on the surface of some bacteria. They are used for attachment and to transfer genetic material. |
| Endospore | A dormant structure that is produced by some Gram-positive bacterial species that are exposed to harsh conditions. |
| Saprophytes | Bacteria that feed on dead and decaying material. |
| Photoautotrophs | Bacteria that use the sun as an energy source. |
| Obligate anaerobes | Bacteria that cannot survive in the presence of oxygen. |
| Faculative anaerobes | Bacteria that can live with or without oxygen. |
| Obligate aerobes | Bacteria that need oxygen to survive. |
| Thermophilic | Bacteria that "love" very hot environments. |
| Transformation | When a bacterial cell takes DNA from its external environment. |
| Conjugation | The process by which two living bacteria bind together and one bacterium transfers genetic information to the other. |
| Conjugation bridge | The specialized pilus that forms a passageway for the transfer of genetic information. |
| Transduction | When a virus obtains a fragment of DNA from a host bacterium. |
| Pathology | The scientific study of disease. |
| Toxins | Disease-causing poisons produced by some bacteria. |
| Exotoxins | Toxins that are made of protein. |
| Endotoxins | Toxins that are made of lipids and carbohydrates. |
| Penicillin | An antibiotic that interferes with cell wall synthesis. |
| Tetracycline | Interferes with bacterial protein synthesis. |
| Broad-spectrum antibiotics | Antibiotics that can affect a wide variety of organisms. |
