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Ch 27 prokaryotes

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242751630peptidoglycanA protein-carbohydrate compound that makes the cell walls of bacteria rigid
242751631gram staina staining technique used to classify bacteria
242751632gram positiveDescribing the group of bacteria that have a cell wall that is structurally less complex and contains more peptidoglycan than the cell wall of gram-negative bacteria. Gram-positive bacteria are usually less toxic than gram-negative bacteria.
242751633gram negativebacteria with a more porous cell wall, does not retain purple stain, appears red/pink/orange after Gram straining procedure
242751634capsulea sticky, gelatinous substance around the cell wall; allows cells to stick together or to the host cell
242751635pilishort, hairlike protein structures on the surface of some bacteria
242751636taxisa locomotor response toward or away from an external stimulus by a motile (and usually simple) organism
242751637nucleoid regionThe region in a prokaryotic cell consisting of a concentrated mass of DNA.
242751638transformation(genetics) modification of a cell or bacterium by the uptake and incorporation of exogenous DNA
242751639conjugationIn bacteria, the direct transfer of DNA between two cells that are temporarily joined.
242751640transduction(genetics) the process of transfering genetic material from one cell to another by a plasmid or bacteriophage
242751641endosporesA thick-walled protective spore that forms inside a bacterial cell and resists harsh conditions
242751642antibioticsmedicines used to kill bacteria and other microorganisms
242751643phototautotrophorganisms that capture light to drive the creation of organic molecules
242751644chemoautotrophorganism that makes organic carbon molecules from carbon dioxide using energy from chemical reactions
242751645photoheterotrophorganism that is photosynthetic but needs organic compounds as a carbon source
242751646chemoheterotrophOrganism that must take in organic molecules for both energy and carbon.
242751647saprobesorganisms that obtain food from decaying organic matter
242751648parasitesan organism that lives in or on another organism, deriving nourishment at the expense of its host, usually without killing it
242751649nitrogen fixationthe assimilation of atmospheric nitrogen by soil bacteria and its release for plant use on the death of the bacteria
242751650obligate aerobesprokaryotes that need oxygen to live
242751651facultative anaerobesbacteria that can live with or without oxygen
242751652obligate anaerobesorganisms that cannot live where molecular oxygen is present
242751653anaerobic respirationRespiration in the absence of oxygen. This produces lactic acid.
242751654signature sequencesRegions of small-subunit ribosomal RNA (SSU-rRNA) that have unique nucleotide sequences acquired by the accumulation of mutations in the ancestor of that taxonomic group.
242751655methanogensArchaebacteria that live in anaerobic environments and produce methane as a by-product of their metabolic process
242751656halophiles"salt-loving" archaea that live in environments that have very high salt concentrations
242751657thermophilesOrganisms that are found in conditions hot enough that most organisms cannot tolerate them.
242751658proteobacteriagram-negative bacteria include photoautotrophs, chemoautotrophs, and heterotrophs, some are anaerobic, and others aerobic, ex. E-Coli: resides in the intestines of many mammals and is not normally pathogenic
242751659cyanobacteriapredominantly photosynthetic prokaryotic organisms containing a blue pigment in addition to chlorophyll
242751660spirochetesspiral-shaped bacteria that have flexible walls and are capable of movement
242751661chlamydiasA group of very small Gram-negative bacteria; they live as intracellular parasites of other organisms.
242751662symbiosisthe relation between two different species of organisms that are interdependent
242751663hostan animal or plant that nourishes and supports a parasite
242751664mutualismsymbiotic relationship in which both species benefit from the relationship
242751665commensalismsymbiotic relationship in which one member of the association benefits and the other is neither helped nor harmed
242751666parasitean animal or plant that lives in or on a host (another animal or plant)
242751667reservoiranything (a person or animal or plant or substance) in which an infectious agent normally lives and multiplies
242751668Koch's postulatesA set of four criteria for determining whether a specific pathogen is the cause of a disease.
242751669exotoxinstoxic substances that bacteria secrete into their environment
242751670endotoxinstoxic substances made of lipids and carbohydrates associated with the outer membrane of gram-negative bacteria
242751671bacteriorhodopsinA photosynthetic pigment found in halophiles. It is very similar to the visual pigments in the retinas of our eyes.

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