MMBIO 221 Exam 2 Robison Study Guide Latest Questions With Solved Correctly Answers!!

Disinfection - destruction of vegetative pathogens; usually on inanimate objects. Antiseptic - agent which prevents bact. contamination and growth; usually on living tissue. Which agent doesn't necessarily work better at higher concentrations? - Alcohol, 70% (goldie lock zone)(60-80% most effective) (Ethyl and Isopropyl) -Alcohol is very effective to resistant to inactivation by organic materials (halogens are not good at this) Name the factors that affect a disinfectant activity. - -Contact Time: longer, the more effective. -Temperature: higher, the more effective. (moist heat better) -pH: depends on chemical; some synergy. -Bioburden: more microbes = longer time. -Types of Microbes: mycobacteria & spores are more difficult to kill. -Extraneous matter: organic matter inhibits many disinfectants. -Proper Exposure: ensure agent gets in. -Disinfectant concentration: higher = better - exception with the alcohols.2 types of antimicrobials - 1. Alteration of cell walls 2. Interference with protein and nucleic acid structure What 3 organisms are used in the AOAC Use-Dilution test? - -Staphylococcus aureus -Pseudomonas aeruginosa -Salmonella choleraesuis How to compute D values (decimal reduction time)- - -Time required to kill 90% (1 log) at a specific temperature. -killed 3 logs in 3 mins = 1 min is the D value Ionizing radiation - High energy Small wavelength (<1nm) Electron beams, gamma, xray -Creating ions -Disrupt H bonds -Oxidize dble covalent bonds -Create Hydroxyl radicals (denature DNA) -Microbes are much more resistant to ionizing radiation than multicellular organisms Non Ionizing radiation - Low energy Large wavelength (>1nm) UV (for air, clear fluid, surfaces) -Excite electrons-New covalent bonds -Affect 3D struct. of proteins and nucleic acids -T-T dimers disrupt H bond (in DNA) -Lesion Antimicrobial handwash - 4% chlorhexidine What Anderson Samplers are used for? - Air Sampling device. Mirrors the human respiratory system. Tests efficacy of filtration system. Bacterial Filtration Efficiency Test -Used to test surgical masks