MIC 206 Biochemical Tests (Daydiff) questions with complete solutions

Phenylalanine Deaminase Test correct answer: Input(s) = amine group Output(s) = pyruvic acid, NH2 Enzyme(s) = phenylalanine deaminase Reagent(s) = 10% FeCl3 pH Indicator = (+) avocado green, (-) clear Principle of Test: - Identifies organisms that can synthesis the enzyme Phenylalanine Deaminase - Deamination reactions remove the amine (N) groups, producing compounds that are acidic. Starch Hydrolysis Test correct answer: Input(s) = starch Output(s) = glucose Enzyme(s) = amylase Reagent(s) = Gram's iodine pH Indicator = (+) clear halo around colonies, (-) blue/black around colonies Principle of Test: - To see if Amylase will break down starch (amylose: long chains of glucose) into individual glucose units. Urea Hydrolysis Test correct answer: Input(s) = urea Output(s) = NH3, CO2 Enzyme(s) = urease Reagent(s) = phenol red pH Indicator = (+) pink (urease positive), (-) yellow Principle of Test: - Identifies organisms that can synthesize the enzyme Urease - In the presence of urease, urea is broken down into ammonia and carbon dioxide. Gelatin Hydrolysis Test correct answer: Input(s) = solid gelatin Output(s) = liquid gelatin Enzyme(s) = gelatinase Reagent(s) = none pH Indicator = (+) liquid medium, (-) solid medium Principle of Test: - Identifies organisms that can synthesis and secrete the enzyme Gelatinase - Organisms that are able to secrete the enzyme gelatinase will liquefy the medium.