Lab Practical Final Study Guide and Photographs

Lab Practical Final Study Guide and Photographs
Medium	Medium Type	Substrate and Biochemical Use	Indicator (s)	Comments
MacConkey Agar Plate shows lactose fermentation by bacteria				What makes this medium selective? What group of bacteria does not grow well on this medium? What group does grow on this medium? What makes this medium a differential medium? Describe possible uses for MacConkey Agar
Eosin Methylene Blue Agar Plate shows lactose fermentation by bacteria				What makes this medium selective? What group of bacteria does not grow well on this medium? What group does grow on this medium? What makes this medium a differential medium? Describe possible uses for Eosin Methylene Blue Agar
Mannitol Salt Agar Plate shows mannitol fermentation by bacteria				What makes this medium selective? What group of bacteria does not grow well on this medium? What group does grow on this medium? What makes this medium a differential medium? Describe possible uses for Mannitol Salt Agar
Biochemical Testing involves giving microbes a type of molecule (also called substrate or nutrient) to see if the microbe produces enzymes that allow the microbe to use the substrate. There has to be some microbe used it. Proof can be an observation of growth or a change in color, based on the reaction between a product of metabolism of the substrate and an indicator chemical.
Catalase	How does the bacterium benefit from the production of this enzyme?	How do you test for the presence of this enzyme?	How do you know if the enzyme is present?	What are the bubbles?
Citrate Utilization What nutrient is used to differentiate bacteria?	negative positive	When a microorganism tests positive for citrate utilization, the citrate has been uses as a source of ?	What metabolic product and indicator chemical allow determination that the nutrient molecule has been used?
Fermentation - Phenol Red Carbohydrate Utilization (Fermentation) Broth – Dextrose, Lactose, Mannitol	negative positive	What nutrient allows differentiation between fermentative and nonfermentative bacteria?	What metabolic product and indicator chemical react to indicate that the nutrient was used?
Methyl Red (MRVP)	negative positive	What nutrient allows differentiation between fermentative bacteria?	What metabolic product and indicator chemical react to indicate that the nutrient was used?	What is the pH at which the indicator chemical changes color?
Gelatin Utilization	negative positive positive	What is the substrate?	How is gelatin utilization determined?	What has happened to the gelatin when the medium is liquid at room temperature?
Tryptophan Hydrolysis - Indole Production (Tryptone Broth	negative positive	When a microorganism tests positive for indole production, what nutrient has it used?	What metabolic product and indicator chemical react to indicate that the nutrient was used?
Hydrogen Sulfide Production (Kligler's Iron Agar)	negative positive	What nutrient is used when a microorganism tests positive for H2S production?	What metabolic product and indicator chemical react to indicate use of the nutrient?
Oxidase	How does the bacterium benefit from the production of this enzyme?	How do you test for the presence of this enzyme?	How do you know if the enzyme is present?
Fluid Thioglycollate Medium	What is the function of this test? In the next block, sketch the expected area of growth for obligate aerobes, facultative anaerobes, microaerophilic bacteria, aerotolerant anaerobes, obligate anaerobes.
Antibiotic susceptibility – Kirby Bauer method			How is susceptibility determined?	What unit of measurement is used to measure the zone of inhibition?