MICRB265 Lecture Notes - Lecture 27: Phospholipid, Vapor Pressure, Extremophile
Document Summary
6-8, water availability; referred to as water activity (aw) Mainly domain bacteria and domain archaea, few eukaryotes. What is normal? mesophilic conditions. temperatures of 20-40 degrees celsius, and ph of. Water it the most important factor controlling growth of microorganisms. Low aw limit for living organisms = 0. 61 if aw is less than 0. 61 then there should be no living. 1. the vapour pressure of pure water. organisms. Profound effect on viability enzyme-catalyzed reactions sensitive to temperature. High temperatures; membrane disruption, enzyme denaturation, dna denaturation. Freezing temperatures; membranes become gel-like, no separation between. Psychrotolerant can grow at 0c, but have mesophilic optimum of 20-40c. phospholipid and protein domains; structure is homogenized.