Campbell Biology - Chapter 27 Flashcards

9378168302	peptidoglycan	A polymer composed of modified sugars cross-linked by short polypeptides. This molecular fabric makes up the cell wall	0
9378168303	Gram stain	A technique that allows scientists to categorize many bacterial species according to differences in cell wall composition.	1
9378168304	Gram-positive	These bacteria tend to have simpler walls with a relatively large amount of peptidoglycan and absorbs more Gram stain.	2
9378168305	Gram-negative	These bacteria tend to have less peptidoglycan, are more structurally complex, with an outer membrane that contains lipopolysaccharides (carbohydrates bonded to lipids) and repels Gram stain.	3
9378168306	capsule	A dense and well-defined sticky layer of polysaccharide or protein that surrounds the cell wall of many prokaryotes.	4
9378168307	endospore	A resistant cell created by certain bacteria that allows it to withstand harsh conditions.	5
9378168309	pili	Appendages that pull two cells together prior to DNA transfer (conjugation) from one cell to the other; tend to be longer and less numerous than fimbriae.	6
9378168310	taxis	A directed movement toward or away from a stimulus, from the Greek "taxis", to arrange.	7
9378168311	nucleoid	A region of cytoplasm containing the prokaryote's genetic material; not enclosed by a membrane.	8
9378168312	plasmids	Smaller rings of independently replicating DNA molecules that only carry a few genes, found in prokaryotic cells, in addition to its single chromosome.	9
9378168313	transformation	The genotype and possibly phenotype of a prokaryotic cell are altered by the uptake of foreign DNA from its surroundings.	10
9378168314	transduction	Phages carry prokaryotic genes from one host cell to another.	11
9378168315	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.	12
9378168316	Obligate aerobes	Prokaryotes that must use oxygen for cellular respiration, and cannot grow without it.	13
9378168317	Obligate anaerobes	Prokaryotes that are poisoned by oxygen, and live by fermentation or anaerobic respiration.	14
9378168318	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.	15
9378168319	Facultative anaerobes	Prokaryotes that use oxygen if it is present but can also carry out fermentation or anaerobic respiration in an anaerobic environment.	16
9378168320	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.	17
9378168321	extremophiles	Prokaryotes that survive in extreme conditions, from the Greek "lover" of extreme conditions.	18
9378168322	Extreme halophiles	Prokaryotes that live in highly saline environments, from the Greek "halo", meaning salt.	19
9378168323	Extreme thermophiles	Prokaryotes that live in very hot environments, from the Greek "thermos", meaning hot.	20
9378168325	decomposers	Prokaryotes that break down dead organisms as well as waste products, thereby unlocking supplies of carbon, nitrogen, and other elements.	21
9378168326	symbiosis	An ecological relationship in which two species live in close contact with each other.	22
9378168327	host	The larger organism in a symbiotic relationship.	23
9378168329	mutualism	An ecological interaction between two species in which both benefit.	24
9378168330	commensalism	An ecological interaction in which one species benefits while the other is not harmed or helped in any significant way.	25
9378168331	parasitism	An ecological relationship in which one species harms another species.	26
9378168332	parasite	The species that harms the other species by eating its cell contents, tissues, or body fluids of its host.	27
9378168333	pathogens	Parasites that cause disease.	28
9378168334	exotoxins	Proteins secreted by certain bacteria and other organisms which cause disease.	29