Test Two

Test Two - Prokaryotes Unicellular colonial forms Range in...

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Prokaryotes Unicellular – colonial forms Range in size from 1-5 um Thiomargarita namibiensis (750um) No membrane-bound organelles Circular chromosomes SHAPES Spheres – cocci Rods-bacilli Spirals – spirilli Cell Wall Maintains cell shape, provides physical protection, prevents cell from bursting in a hypotonic environment Composed of peptidoglycan in bacteria May also have an outer phospholipid membrane Gram-positive – purple Gram-negative – red dye Cell-surface structures A capsule (sticky layer of polysaccharide or protein) may cover the cell wall of many prokaryotes Fimbriae and pilli allow prokaryotes to stick to their substrate or other individuals in a colony Motility Motile bacteria move by means of flagella Structurally different from eukayotic flagella In a heterogeneous environment bacteria exhibit taxis (ability to move toward or away from certain stimuli)
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Positive chemotaxis-moving toward a chemical stimulus Internal organization Pro. Do not have membrane bound organelles Some od have specialized membranes that perform metabolic functions Genomic Organization Prokaryotic chromosome (circular DNA found in the nucleoid region) Not within a nucleus Plasmid (smaller circular DNA rings) Additional genes not always necessary for basic survival Antibiotic resistance Reproduction Pro reproduce quickly by binary fission Can divide every 1-3 hours Form of asexual reproduction Produces genetically identical daughter cells
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Test Two - Prokaryotes Unicellular colonial forms Range in...

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