Microbiology BIOS 242 Exam 2 Questions And Answers With Complete Set

Microbiology BIOS 242 Exam 2 Questions And Answers With Complete Set How Antimicrobial Agents Work and Cellular targets of physical and chemical agents: ✅CCCP(acronym) The cell wall The cell or cytoplasmic membrane Cellular synthetic processes (DNA, RNA) Proteins Temperature ranges of moist heat ✅Temperature ranges from 60 °C to 135 °C Temperature ranges of dry heat ✅Temperature ranges from 160 °C to several thousand degrees Celsius Heat as an Agent of Microbial Control ✅moist heat and dry heat High-level Germicides: ✅High-level Germicides: Kill endospores - sterilant Intermediate -level Germicides: ✅Intermediate -level Germicides: Kill fungal spores, resistant pathogens and viruses Low-level germicides ✅Low-level germicides Eliminate vegetative bacteria, fungal cells and some viruses germicides ✅Agents that destroy pathogenic organisms Germicidal groups ✅Acronym: Dog Ha Ha Halogens (Fluorine, bromine, chlorine, iodine) heavy metals (toxic in small amounts - silver or mercury) Alcohols (ethyl and isopropyl alcohol; 60 -90%) phenolic compounds Oxidizers (H2O2) Aldehydes (Glutaraldehyde and formaldehyde) Detergents (Polar molecules with hydrophilic and hydrophobic regions) Gases (ethylene oxide) Constitutive enzymes: ✅Constitutive enzymes: Always present in relatively constant amounts, regardless of the cellular environment Regulated enzymes: ✅Regulated enzymes: Production is turned on (induced) or turned off (repressed) in response to changes in concentration of substrate Exoenzymes ✅transported extracellularly, where they break down large food molecules or harmful chemicals Endoenzymes ✅retained intracellularly and function there Most enzymes are endoenzymes Stages in the Normal Growth Curve ✅1. lag phase 2. exponential growth phase 3. stationary phase 4. death phase lag phase ✅Flat period on the graph when the population appears not to be growing Newly inoculated cells require a period of adjustment, enlargement, and synthesis Cells are not yet multiplying at their maximum rate Population of cells is so sparse that the sampling misses them exponential growth phase ✅Period during which the growth curve increases geometrically Phase will continue as long as cells have adequate nutrients and the environment is favorable Stationary growth phase: ✅Population enters survival mode Cells stop growing or grow slowly Death phase: ✅Limiting factors intensify and cells begin to die at an exponential rate Curve dips downward Aerobe (aerobic organism) ✅Those that use oxygen and can detoxify it. Can use gaseous oxygen in its metabolism. Possesses the enzymes needed to process toxic oxygen products. Aerobe (aerobic organism) ✅can use gaseous oxygen in its metabolism and possesses the enzymes needed to process toxic oxygen products Obligate aerobe ✅an organism that cannot grow without oxygen Facultative anaerobe ✅organism that can survive with or without oxygen Facultative anaerobe ✅An aerobe that does not require oxygen for its metabolism Capable of growth in the absence of oxygen Metabolizes by aerobic respiration when oxygen is present Adopts anaerobic metabolism (fermentation) when oxygen is absent