BIOLOGY 242 Lecture Notes - Lecture 8: Ionizing Radiation, Pyrimidine Dimer, Membrane Technology
18 Oct 2016
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Chapter 8: control of mos in the environment. Death rates: logarithmic death rate, factors that impact death rate: Concentration: the more mo, the longer to kill. Type of material: density/viscosity/ph (acidic kills best: microbes. Fungal sexual spores, cysts, naked viruses, some bacteria with capsules, mycobacterium sp. More effective than dry heat (denatures proteins) Kill specific mos (pathogens) without affecting flavor or texture: dry heat. Lab utensils, waste disposal: low temperature. Ionizing radiation: x rays and gamma rays (expensive) Causes mutations: dna absorbs radiation at 260 nm, thymine dimers formed. Cannot penetrate well-surfaces/air: mostly disinfects or sanitizes surfaces, filtration: Use vacuum or pressure to get liquid through. Laminar flow biological safety cabinet: standard protoxols: level 1, 2, 3 In lab, we are level 1: level 2 uses cabinet, desiccation. Areus (gram positive) and salmonella typhi (gram negative) Make dilution series of test agents and phenol. If >1, its more effective than phenol **** No agent is 100% perfect: phenolics.
