BIO 105 Lecture Notes - Lecture 29: Biofilm, Extremophile, Prokaryote
Document Summary
Most prokaryotes are bacteria (archaea: a diverse group that live in a wide variety of environments) Short generation time (as quickly as 20 minutes) Cell walls: bacteria have peptidoglycan, archaea do not have peptidoglycan. Growth at temperatures > 100 c: bacteria do not, archaea yes for some species (extremophiles) Play critical roles in chemical cycling e. g. nitrogen- fix atmospheric nitrogen make it available to other organisms. Play critical roles in chemical cycling e. g. nitrogen- fix atmospheric nitrogen make it available to other organisms e. g. carbon-decomposition, photosynthesis. Different structure of flagella in prokaryotes and protists with flagella (eukaryotes) Random movement in a uniform environment high encounter rate with food. Directed movement (taxis) towards clumped food distribution in an environment. Flexible strategy based on food supply in a variable environment only (higher fitness), no flexibility in always clumped or uniform. Taxis: movement towards or away from a stimulus. Due to secretion by community e. g. aquarium hoses, teeth film, stream leaves.
