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Ch. 27 Campbell Bio
Chapter 27: Bacteria and Archae
Question | Answer |
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Peptidoglycan | A type of polymer in bacterial cell walls consisting of modified sugars cross-linked by short polypeptides |
Gram Stain | A staining method that distinguishes between two kinds of bacterial cell walls |
Gram-positive | Describing 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; usually less toxis |
Gram-negative | Describing the group of bacteria that have a cell wall that is structurally more complex and contains less peptidoglyan than te cell wall of gram-positive bacteria; often more toxic |
Capsule | A sticky layer that surrounds the cell wall of some prokaryotes, protecting the cell surface and sometimes glue cells together |
Fimbriae | A short, hairlike appendage of a prokaryotic cell that helps it adhere to the substrate or to other cells |
Plasmids | A small, circular, double-stranded DNA molecule that carries accessory genes separate from those of a bacterial chromosome |
Endospores | A thick-coated resistant cell produced by a bacterial cell exposed to harsh conditions |
Transduction | A type of horizontal gene transfer in which phages carry bacterial DNA from one host cell to another |
Conjugation | In prokaryotes, the direct transfer of DNA between two cells that are temporarily joined |
F Factor | In bacteria, the DNA segment that confers the ability to form pili for conjugation and associated functions required for the transfer of DNA from donor to recipient |
F Plasmid | The plasmid form of the F factor |
R Plasmid | A bacterial plasmid carrying genes that confer resistance to certain antibiotics |
Photoautotrophs | An organism that harnesses light energy to drive the synthesis of organic compounds from carbon dioxide |
Chemoautotrophs | An organism that needs only carbon dioxide as a carbon source but obtains energy by oxidizing inorganic substances |
Photoheterotrophs | An organism that uses light to generate ATP but must contain carbon in organic form |
Chemoheterotrophs | An organism that must consume organic molecules for both energy and carbon |
Obligate aerobes | An organism that requires oxygen for cellular respiration and cannot live without it |
Obligate anaerobes | An organim that only carries out fermentation or anaerobic respiration. Such organisms cannot use oxygen and in fact may be poisoned by it |
Anaerobic Respiration | The use of inorganic molecules other than oxygen to accept electrons at the "downhill" end of the electron transport chain |
Facultative anaerobes | An organism that makes ATP by aerobic respiration if oxygen is present but that switches to anaerobic respiration or fermentation if oxygen is not present |
Nitrogen Fixation | The conversion of atmospheric nitrogen (N2) to ammonia (NH3). Biological nitrogen fixation is carried out by certain prokaryotes, some of which had mutualistic relationships with plants |
Heterocytes | A specialized cell that engages in nitrogen fixation in some filamentous cyanobacteria |
Biofilms | A surface-coating colony of one or more species of prokaryotes that engage in metabolic cooperation |
Extremeophiles | An organism that lives in an environment whose conditions are so extreme that few other species can survive there. |
Extreme halophiles | An organism that lives in a highly saline environment such as the Dead Sea |
Extreme thermophiles | An organism that thrives in hot environments |
Methanogens | An organism that obtains energy by using carbon dioxide to oxidize hydrogen, producing methane as a waste product |
Decomposers | An organism that absorbs nutrients from nonliving organic material such as corpses and converts them to inorganic forms |
Symbiosis | An ecological relationship between organisms of two different species that live together in direct and intimate contact |
Host | The larger participant in a symbiotic relationship, serving as home and food source for the smaller symbiont |
Mutualism | A symbiotic relationship in which both participants benefit |
Commensalism | A symbiotic relationship in which one organism benefits but the other is neither helped nor harmed |
Parasitism | A symbiotic relationship in which one organism, the parasite, benefits at the expense of another, the host, by living either within or on the host |
Parasite | An organism that feeds on the cell contents, tissues or body fluids of another species while in or on the host organism; usually do not kill host |
Pathogen | An organism or virus that causes disease |