Campbell Biology - Chapter 27 Flashcards

9372551234	peptidoglycan	A polymer composed of modified sugars cross-linked by short polypeptides. This molecular fabric encloses the entire bacterium and anchors other molecules that extend from its surface.	0
9372551235	Gram stain	A technique that allows scientists to categorize many bacterial species according to differences in cell wall composition.	1
9372551236	Gram-positive	These bacteria tend to have simpler walls with a relatively large amount of peptidoglycan.	2
9372551237	Gram-negative	These bacteria tend to have less peptidoglycan, are more structurally complex, with an outer membrane that contains lipopolysaccharides (carbohydrates bonded to lipids).	3
9372551238	capsule	A dense and well-defined sticky layer of polysaccharide or protein that surrounds the cell wall of many prokaryotes.	4
9372551239	endospore	A resistant cell created by certain bacteria that allows it to withstand harsh conditions. The original cell produces a copy of its chromosome and surrounds that copy with a tough multilayered structure, forming the endospore.	5
9372551240	fimbriae	hair-like appendages that allow prokaryotes to stick to their substrate or to one another.	6
9372551241	pili	Appendages that pull two cells together prior to DNA transfer from one cell to the other; tend to be longer and less numerous than fimbriae.	7
9372551242	taxis	A directed movement toward or away from a stimulus, from the Greek "taxis", to arrange.	8
9372551243	nucleoid	A region of cytoplasm containing the prokaryote's genetic material; not enclosed by a membrane.	9
9372551244	plasmids	Smaller rings of independently replicating DNA molecules that only carry a few genes, found in prokaryotic cells, in addition to its single chromosome.	10
9372551245	transformation	The genotype and possibly phenotype of a prokaryotic cell are altered by the uptake of foreign DNA from its surroundings.	11
9372551246	transduction	Phages carry prokaryotic genes from one host cell to another.	12
9372551247	conjugation	DNA is transferred between two prokaryotic cells (usually of the same species) that are temporarily joined. In bacteria, the DNA transfer is always one-way: One cell donates the DNA, and the other receives it.	13
9372551248	Obligate aerobes	Prokaryotes that must use oxygen for cellular respiration, and cannot grow without it.	14
9372551249	Obligate anaerobes	Prokaryotes that are poisoned by oxygen, and live by fermentation or anaerobic respiration.	15
9372551250	Anaerobic respiration	A form of respiration in which substances other than oxygen, such as nitrate or sulfate ions accept electrons at the "downhill" end of electron transport chains.	16
9372551251	Facultative anaerobes	Prokaryotes that use oxygen if it is present but can also carry out fermentation or anaerobic respiration in an anaerobic environment.	17
9372551252	Nitrogen fixation	The process, carried out by some cyanobacteria and some methanogens, of converting atmospheric nitrogen to ammonia, which can then be incorporated into amino acids and other organic molecules.	18
9372551253	extremophiles	Prokaryotes that survive in extreme conditions, from the Greek "lover" of extreme conditions.	19
9372551254	Extreme halophiles	Prokaryotes that live in highly saline environments, from the Greek "halo", meaning salt.	20
9372551255	Extreme thermophiles	Prokaryotes that live in very hot environments, from the Greek "thermos", meaning hot.	21
9372551256	methanogens	Archaea that release methane as a by-product of their unique ways of obtaining energy. Many use carbon dioxide to oxidize hydrogen gas, which produces both energy and methane waste.	22
9372551257	decomposers	Prokaryotes that break down dead organisms as well as waste products, thereby unlocking supplies of carbon, nitrogen, and other elements.	23
9372551258	symbiosis	An ecological relationship in which two species live in close contact with each other.	24
9372551259	host	The larger organism in a symbiotic relationship.	25
9372551260	symbiont	The smaller organism in a symbiotic relationship.	26
9372551261	mutualism	An ecological interaction between two species in which both benefit.	27
9372551262	commensalism	An ecological interaction in which one species benefits while the other is not harmed or helped in any significant way.	28
9372551263	parasitism	An ecological relationship in which one species harms another species.	29
9372551264	parasite	The species that harms the other species by eating its cell contents, tissues, or body fluids of its host.	30
9372551265	pathogens	Parasites that cause disease.	31
9372551266	exotoxins	Proteins secreted by certain bacteria and other organisms which cause disease.	32
9372551267	endotoxins	Lipopolysaccharide components of the outer membrane of gram-negative bacteria. They are released only when the bacteria die and their cell walls break down.	33
9372551268	bioremediation	The use of organisms to remove pollutants from soil, air, or water.	34
9372551269	Chlamydias	parasites that live within animal cells (gram negative)	35
9372551270	Cyanobacteria	Photosynthetic, oxygen-producing bacteria (formerly known as blue-green algae).	36
9372551271	Halophiles	"salt-loving" archaea that live in environments that have very high salt concentrations	37
9372551272	Thermophiles	Prokaryotes that thrive in very high temperatures	38
9372551273	Methanogens	Prokaryotes that synthesize methane from carbon dioxide and hydrogen gas	39
9372551274	Phototrophs	obtain energy from light	40