BIOL 2051 Chapter : Chapter 5
Document Summary
Chapter 5 - environmental influences and control of microbial growth. Environmental factors that affect microbial growth: temperature, pressure, osmolarity, ph, oxygen. Induced by many stressful conditions: heat, high salt concentrations, arid conditions. Pressure: barophiles, adapted to high pressures, up to 1,000 atm, barotolerant organisms, barosensitive organisms, die at high pressure, grow at high, but not very high pressure, most typical bacteria, all mammals. In a _____________ environment water will move _________ a cell & the cell will. In a hypotonic environment the cell wall of most prokaryotes prevents too much water from entering cells even if equilibrium is never reached: cells may swell but won"t lyse. About 3% salt in ocean: extreme halophiles require high levels (15-30%) of salts for growth. Halobacterium salinarium lives in very salty lakes (requires 25% salt: halotolerant organisms can survive at higher salt concentrations but grow best in absence of salt.
