BIOL 2051 Chapter : Chpt 5 2 Larry
Document Summary
Chapter 5 - environmental influences and control of microbial growth. Environmental factors that affect microbial growth: temperature, pressure, osmolarity, ph, oxygen. Temperature is a major environmental factor controlling microbial growth. _____cardinal______ temperatures- minimum, optimum, & maximum temps for an organism. ________minimum____________ temperature - cellular processes _____slow________; cytoplasmic membranes stiffen. ______optimum temperature______________ temperature- organism grows best; between min & max: microorganisms can be grouped by the temperature ranges they require, psychrophiles (cold temps, cold: o c 20 c. Extreme thermophiles: 65 c 113 c, psychrophiles- found in constantly cold environments. Example: chlamydomonas: molecular adaptations of psychrophiles, membranes have high content of unsaturated fatty acids- semi- fluid at low temperatures. ____proteins are more flexibale____________ compared to mesophiles or thermophiles. ______cryoprotectants___________ can be used to preserve microbial cultures at ____low temps_______ _____dmso__________ (dimethylsulfoxide) & ___10% glycerol________________ are commonly used in laboratories to preserve microbial cultures for long time in freezers: mesophiles- midrange optimum temperature.
