Chapter 27 Vocab - Summary Campbell Biology PDF

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Chapter 27: Prokaryotes 27.1 “Structural, functional, and genetic adaptations contribute to prokaryotic success” Cell-Surface Structures 

Peptidoglycan- a network of modified-sugar polymers cross-linked by short polypeptides

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Gram Stain- a technique that can classify many bacterial species into two groups based on differences in cell wall composition.

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Gram-Positive- bacteria that have simpler walls with a relatively large amount of peptidoglycan

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Gram-Negative- bacteria that have less peptidoglycan and are structurally more complex, with an outer membrane that contains lipopolysaccharides

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Capsule- a sticky layer of polysaccharide or protein. Allows prokaryotes to adhere to their substrate or to other individuals or other individuals in a colony

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Fimbriae- hairlike appendages, numerous and short

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Pili- hairlike appendages, used for conjugation Motility

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Taxis- movement toward or away from a stimulus

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Chemotaxis- response to chemicals by changing movement pattern

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Positive Chemotaxis- movement toward a chemical stimulus

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Negative Chemotaxis- movement away from a chemical stimulus

Internal and Genomic Organization 

Nucleoid Region- where prokaryotic chromosomes are located; part of the cytoplasm that appears lighter than the surrounding cytoplasm in electron micrographs

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Plasmids- small rings of DNA that consists of only a few genes; provide resistance to antibiotics, direct the metabolism, and other contingency functions Reproduction and Adaptation

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Endospores- resistant cells that form when essential nutrient is lacking from the environment 27.2 “A great diversity of nutritional and metabolic adaptations have evolved in prokaryotes”

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Photoautotrophs- photosynthetic organisms that capture light energy to use it to drive the synthesis of organic compounds from CO₂ (Cyanobacteria); obtain energy from the light

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Chemoautotrophs- organisms that only need CO₂ as a carbon source. Instead of light energy, they oxidize inorganic substances, such as hydrogen sulfide (H₂S), Ammonia (NH₃) or ferrous ions (Fe²⁺); obtain energy from chemicals

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Photoheterotrophs- organisms who use light for energy but must obtain their carbon in organic form

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Chemoheterotrophs- organisms that must organic molecules for both energy and carbon

Metabolic Relationships to Oxygen

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Obligate Aerobes- prokaryotes that use O2 for cellular respiration and cannot grow without it

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Facultative Anaerobes- prokaryotes that use O2 if it is present but can also grow by fermentation in an anaerobic environment

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Obligate Anaerobes- poisoned by O2

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Anaerobic Respiration- The use of inorganic molecules other than oxygen to accept electrons at the "downhill" end of electron transport chains Nitrogen Metabolism

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Nitrogen Fixation- a process where prokaryotes convert nitrogen (N₂) to ammonia (NH₃) to be incorporated into amino acids and other organic material Metabolic Cooperation

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Anabaena- a cyanobacterium that has genes encoding proteins for photosynthesis and nitrogen fixation, but cannot do these processes simultaneously

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Heterocytes- specialized nitrogen-fixing cells

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Biofilms- a surface-coating colony of prokaryotes that engage in metabolic cooperation 27.3 “Molecular systematics is illuminating prokaryotic phylogeny” Archaea

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Extremophiles- lovers of extreme conditions. Include extreme thermophiles, extreme halophiles, and methanogens

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Extreme Thermophiles- prokaryotes that thrive in very hot conditions

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Extreme Halophiles- prokaryotes that thrive in highly saline environments, such as the Great Salt Lake and the Dead Sea

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Methanogens- prokaryotes that use CO2 to oxidize H2, releasing methane as a waste product 27.4 “Prokaryotes play crucial roles in the biosphere”

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Decomposers- organisms that break down corpses, dead vegetation and waste products thereby unlocking supplies of carbon, nitrogen, and other elements Symbiotic Relationships

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Symbiosis- ecological relationship between organisms of different species that are in direct contact

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Host- larger symbiotic organism

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Symbiont- smaller symbiotic organism

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Mutualism- an ecological relationship where both symbiotic organisms benefit

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Commensalism- an ecological relationship where one organism benefits while neither harming nor helping the other in any significant way

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Parasitism- an ecological relationship where one organism benefits at the expense of the host

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Parasite- an organism that lives in or on another organism (its host) and benefits by deriving nutrients at the host's expense 27.5 “Prokaryotes have both harmful and beneficial impacts on humans” Pathogenic Prokaryotes

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Exotoxins- proteins secreted by prokaryotes (Cholera)

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Endotoxins- lipopolysaccharide components of the outer membrane of gramnegative bacteria. (Salmonella) Prokaryotes in Research and Technology

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Bioremediation- the use of organisms to remove pollutant from soil, air, or water...