Ch. 27 Bacteria and Archaea
masters of adaptation
prokaryotes in the domain Archara and Bacteria are capable of surviving extreme conditions
Halobacterium are examples of these prokaryotes that can handle extreme conditions
Halobactreium pumps potassium ions into the cell until the ionic concentration inside the cell match es the concentration outside
Some prokaryotes live in conditions too cold or too hot for most life
ability to adapt explains why they're the most abundant creatures on earth
Structural and functional adaptations contribute to prokaryotic success
First organisms to inhabit earth were prokaryotes
subject to natural selection, resulting in enormous diversity
typically unicellular
diameter of .5-5um, much smaller than eukaryotes
variety of shapes
well organized
Cell-surface structure
cell wall maintains shape, protects the cell, and prevents from bursting
cell wall differs in structure
eukaryotes have cell walls, like plants and fungi, walls are usually made of chitin and cellulose
most bacteria cell walls have peptodeclycon, polymer composed of modified sugars cross linked by short polypeptides
archeae lack peptidoglycan
Gram Stain- method of categorizing many bacterial species by cell wall compensation
sample is stained with iodine, rinsed with alcohol, and then stained red
Gram-Positive: simple walls composed of thick layer of peptidoglycan
Gram-negative: less peptidoglycan and are more complex, outer membrane that contains lipopolysaccharides
lipid portion of lipopolysaccharides is toxic, causing sickness
capsule- cell wall of prokaryotes is surrounded by sticky layer of polysaccharide or ported
enables them to adhere to substrate
endospores- types of cells that lack water or essential nutrients
fimbriae- sticking to substance using hair like particles
Motility
Taxis- movement towers or away from stimulus
chemotaxis- changing direction in response to chemicals
positive chemotaxis- move towards nutrients or oxygen
negative chemotaxis- away from toxic substances
some species can move up to 50x their body length per second
Evolutionary origins of Bacterial Flagella
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