BIO 1305 Lecture Notes - Lecture 5: Gram Staining, Gram-Negative Bacteria, Gram-Positive Bacteria
16 Dec 2017
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Gram positive bacteria have simpler walls with large amount of peptidoglycan. Gram negative bacteria have less peptidoglycan and an outer membrane that contains lipopolysaccharide. Gram negative bacteria also tend to be more resistant than gram. + species to antibiotics because the outer membrane impedes entry of drugs. Endospores: resistant cells that withstand conditions, copy chromosome and surround chromosome to protect, dormant survive harsh environments, rehydrate in favorable (anthrax) Cell walls of prokaryotes is surrounded by a sticky layer of polysaccharide/protein called a capsule if it"s dense and well defined or slime layer if its disorganized: describe the common shapes of prokaryotes. Coccus-sphere (singular, clumped in pairs, chains, clustered), baccilus-rod (typically singular, can also form chains), spiral: t/f eukaryotic and prokaryotic flagella are homologous structures. Explain your answer. (discuss the motility of prokaryotes and the structure of flagella) Bacteria exhibit taxis- the ability to move toward/away from a stimulus. Chemotaxis: positive- move towards nutrients/oxygen; negative- move away from toxic substances.
