BIOL 1202 Chapter : Prokaryotes
Document Summary
One thing the e. coli and other bacteria have in common with eukaryotes is the presence of ribosomes. Cell wall- maintains shape, provides physical protection, prevents cell from bursting in a hypotonic environment. May also have an outer phospholipid membrane. A capsule (a 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. Gram negative bacteria have less peptidoglycan than gram-positive cells and their cell walls are more complex structurally. Bacteria____: have a single circular chromosome. Motile bacteria move along by means of flagella: structurally different from eukaryotic flagella. In a heterogeneous environment bacteria exhibit taxis (ability to move toward or away from certain stimuli: ex: positive chemotaxis- moving toward a chemical stimulus. Some do have specialized membranes that preform metabolic functions: aerobic prokaryotes; respiratory membrane. Prokaryotic chromosome (circular dna found in the nucleoid region: not within a nucleus.
