Lab Test 2 Review - Emphasis - Cultural Characteristics, Physiological (Biochemical) Characteristics Testing

Biochemical Testing involves giving microbes a substrate to see if it can use it.  There has to be some way to prove the microbe used it.  Proof can be an observation of growth or a change in color that based on the reaction between a product of metabolism and an indicator chemical. 

Selective and Differential Media - See link at the bottom of this page.

Carbohydrate Fermentation - Phenol Red Carbohydrate Fermentation Broth (Glucose, Lactose, Mannitol) - Lab Manual p.231-232
What substrate is used to differentiate between fermentative and nonfermentative bacteria?  What metabolic product and indicator chemical react to indicate that the substrate was used?
Methyl Red Test (MRVP medium) - Lab medium p.231-234
What substrate is used to differentiate fermentative bacteria?  What metabolic product is formed?  How is the presence of the metabolic product determined?  What pH causes the indicator chemical to change color?
Catalase - Lab Manual p.234-235
What substrate is used to determine the presence of catalase?  When a microorganism tests positive for catalase production, what does this indicate about the bacteria?  What metabolic products are formed from this reaction?
Oxidase - Lab Manual p.235
What substrate is used to determine the presence of oxidase?  Which bacteria test positive for oxidase?
Citrate Utilization - Lab Manual p.241-242
What substrate is used to differentiate bacteria?  When a microorganism tests positive for citrate utilization, how is the citrate used?  What metabolic product and indicator chemical allow determination that the nutrient substrate has been used?

Tryptophan Hydrolysis (Indole Production) Tryptone Broth - Lab Manual p.239-240
When a microorganism tests positive for indole production, what substrate has it used and what additional metabolic product was formed?  What metabolic product and indicator chemical react to indicate that the nutrient substrate was used? 

Hydrogen Sulfide Production using Kligler's Iron Agar - Lab Manual p.241-242
What substrate is used when a microorganism tests positive for H2S production?  What metabolic product and indicator chemical react to indicate use of the substrate?  What other metabolic product is formed in this reaction?
Gelatin Stab Culture (Gelatin Liquefaction) - Lab Manual p.227
What substrate is used when the medium is liquid at room temperature?  What enzyme is produced by the bacteria that catalyzes this reaction?
Fluid Thioglycollate Medium - Lab Manual p. 227
What is the primary function of inoculating a tube of fluid thioglycollate medium?

Antibiotic susceptibility – Kirby Bauer method
How is susceptibility determined?  What unit of measurement is used to measure the zone of inhibition?

Click here for more questions and photos