Chapter 27 Prokaryotes

Chapter 27 Prokaryotes - Chapter 27 Prokaryotes One thing...

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Chapter 27 Prokaryotes One thing that E. coli and other bacteria have in common with eukaryotes is the presence of ribosomes ? - prokaryotes do not have membrane bound organelles (chloroplasts, mitochondria, and nucleus) Concept 27.1 Structural and functional adaptations contribute to prokaryotic success prokaryotes are unicellular -- some colonial forms Range in size from 1-5 um -- Thiomargita namiensis (750 um) No membrane bound organelles Circular chromosomes Prokaryotic cells have a variety of shapes The three most common are spheres (cocci), rods (bacilli), and spirals (spirilli) Cell-Surface Structures Cell wall o Maintains cell shape, provides physical protection, prevents cell from bursting in a hypotonic environment o Composed of peptidoglycan in bacteria o May also have an outer phospholipid membrane Cell-Surface Structures - 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 - 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 CQ – Gram-negative bacteria have _less_ peptidoglycan than gram-positive cells and their cell walls are _more_ complex structurally **Gram-negative and Gram positive Motility - Motile backeria move by means of flagellae --- Structurally different from eukaryotic flagella
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- In a heterogeneous environment bacteria exhibit taxis (ability to move toward or away from certain stimuli)
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This note was uploaded on 03/18/2010 for the course BIOL 1202 taught by Professor Gregg during the Spring '08 term at LSU.

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Chapter 27 Prokaryotes - Chapter 27 Prokaryotes One thing...

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