Presentation on theme: "Physical Factors Exp 15: Temperature Exp 16: pH Exp 17/18: O 2 Requirements Week 11B Last week: We Start our Unknown Project today! Exp. 69: Species Identification."— Presentation transcript:
Physical Factors Exp 15: Temperature Exp 16: pH Exp 17/18: O 2 Requirements Week 11B Last week: We Start our Unknown Project today! Exp. 69: Species Identification of Unknown Bacterial Cultures Part 1: Gram Stain and Isolation Technique New This Week: Exp 43: Chemical Agents of Control: Chemotherapeutic Agents; Part A: Kirby Bauer Antibiotic Sensitivity Test
Exp 15: Physical Factors: Temperature Any organism has a Min., Max. and an Optimum growing temperature. –High temperatures: enzyme denatures and cells die. –Low temperatures: enzyme activity is lower & cell deprived of H 2 O. Organisms will grow at various temperature ranges: –Psychrophile cold-loving -5 o - 20 o C –Mesophile- moderate temps. – will grow at body temps 20 o - 45 o C most pathogens 37 o C –Thermophile - heat loving 35 o C
Exp 16: Physical Factors: pH of the Extracellular Environment pH - measure of [H+] ion concentration in a solution –Low pH - end products of carbohydrate metabolism are organic acids (yeasts). –High pH - end products of breakdown of proteins are amines and ammonia. Specific pH needs reflect adaptations to environment (ex enteric bacteria can survive in broad pH while bacterial blood parasites have a narrow pH range). Lab medium frequently adjusted to neutral pH since best for growth thus use buffers.
Exp. 69: Species Identification of Unknown Bacterial Cultures Unknown project overview. Requisition Forms. Written report. Part 1: –Isolation Technique –Gram Stain –Differential Media
Epidemiology: the science of when and where diseases occur and how they are transmitted Descriptive (data on occurrence) Analytical (probable cause) Experimental (hypothesis, test) CDC, Center for Disease Control, US Public Health Service
Exp 43: Chemical Agents of Control: Chemotherapeutic Agents Part A: Kirby Bauer Antibiotic Sensitivity Test
Measures drug efficacy by measuring diameter of zone of inhibition Susceptibility of organism to drug is determined by the size of the zone. Medium of choice for this test is Mueller-Hinton agar