Question 42 You would like to determine if the bacteria is lipase-positive. Your choice of medium would be __. A nutrient agar containing starch B nutrient agar containing glucose C nutrient agar containing casein D Spirit Blue agar E nutrient agar containing salt Additional content
Added by Virginia I.
Close
Step 1
Lipase is an enzyme that breaks down lipids (fats). Therefore, to test for lipase activity, the medium must contain a lipid that can be hydrolyzed by the enzyme, and there should be an indicator to show this hydrolysis. Step 2: Analyze the options: A. Nutrient Show more…
Show all steps
Your feedback will help us improve your experience
Adi S and 86 other Biology educators are ready to help you.
Ask a new question
Labs
Want to see this concept in action?
Explore this concept interactively to see how it behaves as you change inputs.
Key Concepts
Recommended Videos
color of milk. The medium can be used to identify test organisms capable of producing the enzyme caseinase to hydrolyze casein to form soluble clear nitrogenous compounds displayed as a clear zone around positive colonies cloudy white medium. Lipase activity Spirit Blue agar. An all-purpose medium that contains a simple triglyceride Tributyrin that serves as the substrate enzyme lipase and the spirit blue dye. Hydrolysis of Tributyrin by lipase activity results in the release of fatty acid lowers the pH of the agar to produce a dark blue precipitate around the colonies of the lipase-producing test orga Gram's iodine solution Starch Agar Plate (Amylase activity) Skim Milk Agar (Caseinase activity) Spirit Blue Agar (Lipase activity) Interpretation Bacteria 1 Bacillus subtilis Clear zone around colony Clear zone around growth Dark blue ppt around growth 2 Escherichia coli No clear zone around growth No clear zone around growth No dark blue ppt around growth 3 Staphylococcus aureus No clear zone around growth No clear zone around growth Dark blue ppt around growth 4 Pseudomonas aeruginosa No clear zone around growth Clear zone around growth Dark blue ppt around growth QUESTIONS: 1. List all the test bacteria in the table that tested positive for amylase enzyme. 2. List all that tested positive for protease enzyme. 3. List all that tested positive for lipase enzyme. 4. What is the pH indicator used in the test medium for lipase activity?
Adi S.
Lipase activity Spirit Blue agar. An all-purpose medium that contains a simple triglyceride Tributyrin that serves as the substrate for the enzyme lipase and the spirit blue dye. Hydrolysis of Tributyrin by lipase activity results in the release of fatty acids which lowers the pH of the agar to produce a dark blue precipitate around the colonies of the lipase-producing test organism. Gram's Iodine solution Bacteria Starch Agar Plate (Amylase activity) Skim Milk Agar (Caseinase activity) Spirit Blue Agar (Lipase activity) 1 Bacillus subtilis Clear zone around colony Clear zone around growth Dark blue ppt around growth 2 Escherichia coli No clear zone around growth No clear zone around growth No dark blue ppt around growth 3 Staphylococcus aureus No clear zone around growth No clear zone around growth Dark blue ppt around growth 4 Pseudomonas aeruginosa No clear zone around growth Clear zone around growth Dark blue ppt around growth QUESTIONS: 1. Identify all the test bacteria in the table that tested positive for amylase enzyme. 2. Identify all that tested positive for protease enzyme 3. Identify all that tested positive for lipase enzyme 4. What is the pH indicator used in the test medium for lipase activity? Deaminases Deaminases are enzymes that can degrade amino acids and generate smaller molecules that can be used for metabolic purposes. There are 20 naturally occurring amino acids and as such there are 20 different deaminases. So each amino acid has a specific deaminase. Generally, deaminases remove the amino group (-NH2) from the amino acid and converted to ammonia, the rest of the molecule is converted to alpha keto acid. In some amino acids, the resulting alpha keto acid is stable and can be detected as an end product as Phenyl pyruvic acid from Phenylalanine. In some amino acids the alpha keto acid is further broken down to other end products such as Indole that results from indole pyruvic acid and amino acid Tryptophan. Indole in the medium is the basis for the test that differentiates bacteria that produce tryptophanase from those that do not produce the enzyme
a. A culture medium with a high NaCl salt concentration would be considered selective for salt-tolerant species. b. Which of these formulations is considered a complex culture medium? c. Glucose, ammonium salts, magnesium sulfate, sodium phosphate, trace minerals, water. d. Yeast extract, peptone, glucose, NaCl, water. e. Lactose, beef extract, glycerol, agar, water. f. Just a). g. Both b) and c). h. All 3 are complex. i. Which lab instrument is used to make a streak plate? j. Needle. k. Loop. l. Pipette. m. Swab. n. Spectrophotometer. o. To prevent light scattering when using the highest powered objective in the light microscope, what is applied to the slide? p. Extremely bright light. q. Very low light. r. Alcohol. s. Oil. t. Spit.
John N.
Recommended Textbooks
Biology for AP Courses
Objective Biology for NEET
Introduction to General, Organic and Biochemistry
Transcript
Watch the video solution with this free unlock.
EMAIL
PASSWORD