| A | B |
|---|
| Coccus | A spherical-shaped bacterial cell. |
| Bacillus | Bacterial cell shape that is cylindrical (rod-like) (longer than it is wide) |
| Coccobacillus | An elongated coccus; a short thick oval-shaped bacterial rod. |
| Vibrio | A curved rod-shaped bacterial cell. |
| Spirillum | A type of bacterial cell with a rigid spiral shape and external flagella. |
| Spirochete | A coiled spiral shaped bacterium that has endoflagella and flexes as it moves. |
| Tetrads | Group of four |
| Sarcina | A cubical packet of 8- 16 or more cells. |
| Appendages | Accessory structures that sprout from the surface of bacteria. They can be divided into 2 major groups – those that provide movement and those that enable adhesion (sticking). |
| Flagellum | A structure that is used to propel the organism through a fluid environment. |
| Motility | Self-propulsion. |
| Filament | A helical structure composed of proteins that is part of bacterial flagella. |
| Monotrichous | Describing a microorganism that bears a single flagellum. |
| Lophotrichous | describing a microorganism that has small bunches or tufts of flagella emerging from the same site |
| Amphitrichous | Having a single flagellum or a tuft of flagella at opposite poles of a microbial cell. |
| Peritrichous | In bacterial morphology having flagella distribute over the entire cell. |
| Chemotaxis | The tendency of organisms to move in response to a chemical gradient (toward an attractant or to avoid adverse stimuli). |
| Run | a type of bacteria movement in which the flagellum rotates counter-clockwise which causes the cell to swim in a smooth linear direction. |
| Tumble | this movement often interrupts a “run”- the flagellum reverses direction and causes the cell to stop and change its course. |
| Phototaxis | The movement of organism in response to light. |
| axial filament | A type of flagellum that lies in the periplasmic space of spirochetes and is responsible for locomotion. |
| Pilus | A hollow appendage used to bring two bacterial cells together to transfer DNA. |
| Fimbria | A short numerous-surface appendage on some bacteria that provides adhesion but not locomotion. |
| Pilin | a special protein that makes up a pilus. |
| Conjugation | In bacteria the contact between donor and recipient cells associated with the transfer of genetic material such as plasmids |
| S layer | Single layer of thousands of copies of single type of proteins linked together on the surface of a bacterial cell that is produced when the cell is in a hostile environment. |
| Glycocalyx | a filamentous network of carbohydrate-rich molecules that coats cells. |
| slime layer | A diffuse unorganized layer of polysaccharides and/or proteins on the outside of some bacteria. |
| Capsule | In bacteria the loose gel-like covering or slime made chiefly of polysaccharides. This layer is protective and can be associated with virulence. |
| Biofilm | A complex association that arises from a mixture of microorganisms growing together on the surface of a habitat |
| Gram stain | A differential stain for bacteria useful in identification and taxonomy. Gram-positive organisms appear purple from crystal violet mordant retention whereas gram-negative organisms appear red after loss of crystal violet and absorbance of the safranin counterstain. |
| gram-positive | A category of bacterial cells that describes bacteria with a thick cell wall and no outer membrane. |
| gram-negative | A category of bacterial cells that describes bacteria with an outer membrane a cytoplasmic membrane and a thin cell wall. |
| cell wall | In bacteria a rigid structure made of peptidoglycan that lies just outside the cytoplasmic membrane. |
| Peptidoglycan | A network of polysaccharide chains cross-linked by short peptides that forms the rigid part of bacterial cell walls. Gram-negative bacteria have a smaller amount of this rigid structure than do gram-positive bacteria. |
| Lysis | The physical rupture or deterioration of a cell. |
| mycolic acid | A thick wavy long chain fatty acid found in the cell wall of Mycobacterium and Nocardia that confers resistance to chemical and dyes. |
| acid-fast stain | A solution containing carbol fuchsin which when bound to lipids in the envelopes of Mycobacterium species cannot be removed with an acid wash. |
| Mycoplasmas | A genus of bacteria. Contain no peptidoglycan/cell wall but the cytoplasmic membrane is stabilized by sterols. |
| Pleomorphic | Normal variability of cell shapes in a single species. |
| outer membrane | An additional membrane possessed by gram-negative bacteria. A lipid bilayer containing specialized proteins and polysaccharides. It lies outside of the cell wall. |
| Lipopolysaccaharide | A molecular complex of lipid and carbohydrate found in the bacterial cell wall. The lipopolysaccharide (LPS) of gram-negative bacteria is an endotoxin with generalized pathologic effects such as fever. |
| Endotoxin | A bacterial toxin that is not ordinarily released (as is exotoxin). Endotoxin is composed of a phospholipid-polysaccharide complex that is an integral part of gram-negative bacterial cell walls. |
| porin proteins | Transmembrane proteins of the outer membrane of gram-negative cells that permit transport of small molecules into the periplasmic space but bar the penetration of larger molecules. |
| cytoplasmic membrane (cell membrane) | Lipid bilayer that encloses the cytoplasm of bacterial cells. |
| selectively permeable | Describe a property of cell membrane in which certain substances are able to pass through the membrane while other substances cannot pass through unaided and require special carrier proteins in order to enter or exit the cell. |
| Secretion | the discharge of a metabolic product into the extracellular environment. |
| Cytoplasm | Dense fluid encased by the cell membrane. The site of many of the cell's biochemical and synthetic activities. |
| bacterial chromosome | A circular body in bacteria that contains the primary genetic material. Also called nucleoid. |
| Nucleoid | The basophilic nuclear region or nuclear body that contains the bacterial chromosome. |
| Plasmid | exist as separate double-stranded circles of DNA that is smaller than and replicates independently of the cell chromosome. |
| inclusion bodies (inclusions) | A relatively inert body in the cytoplasm such as storage granules glycogen fat or some other aggregated metabolic product. |
| Endospore | A small dormant resistant derivative of a bacterial cell that germinates under favorable growth conditions into a vegetative cell. The bacterial genera Bacillus and Clostridium are typical sporeformers. |
| Sporulation | The process of spore formation. |
| Archaea | Prokaryotic single-celled organisms of primitive origin that have unusual anatomy physiology and genetics and live in harsh habitats. |
| Methanogens | Methane producers. |
| Psychrophile | A microorganism that thrives at low temperature (0-20 Celsius) with a temperature optimum of 0-15 Celsius. |
