Nutrient agar is general purpose nutrient media used for cultivation of microb growth of wide range of non-fastidious organisms. Nutrient agar is popular be variety of types of bacteria and fungi and contains many nutrients needed for Due to it comparison of growth quality of various microorganisms can be don Q3. Proteus species and certain species of Salmonella produce a black precipit on Hektoen. Chemically what is occurring to cause the black precipitate to for ingredients in the media are being used by the bacteria to produce the black pre Q4. With respect to MacConkey agar, what would be the possible consequence a)replacing the lactose with glucose? Would you be able to distinguish EC from glucose instead? Explain. (Exercise 7 results will help here with this question). b)replacing the neutral red with phenol red (yellow when acidic; red or pink when Q5. For these questions refer to introductory pages of Ex. 5-20: a)What happens to blood agar when an alpha-hemolytic reaction occurs? b)What happens when a beta-hemolytic reaction occurs? c)What happens when a gamma-hemolytic reaction occurs?
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This gas reacts with the ferrous sulfate in the agar, forming a black precipitate of ferrous sulfide. Show more…
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You inoculated a MacConkey agar plate with a gram-positive and a gram-negative bacterial strain. When you observe the plate after incubation, you notice that only the gram-negative bacteria formed colonies. In addition, you notice there is a color change in the media (red to yellow), indicating that this gram-negative bacterium is capable of lactose fermentation. What type of media is this? a) selective b) Differential c) All of the above 2. Fannie Hesse developed the idea of replacing gelatin with agar. What are the benefits of using agar over gelatin? a) Agar is cheap and a good solidifying agent b) Gelatin melts at a lower temperature (40 degrees Celsius), whereas agar does not. c) Agar is a great nutrient source for most bacteria. d) Answer A and B are correct 3. You have been instructed to measure an overnight culture for bacterial density. Which of the following methods would you use if you do not care about distinguishing dead from live bacterial cells? a) Membrane filtration method b) Turbidity c) Most probable number d) Plate count using the spread plate method e) Plate count using the pour plate method.
Sri K.
5. What is agar? 6. How is blood agar used to differentiate between different bacteria? 7. Describe β-hemolysis. What enzyme is responsible? 8. What information about the pathogen did the results of the Gram stain reveal? 9. Describe the procedure for an ELISA test. 10. Based on the lab results, what pathogen is causing Billy's illness? Their doctor reviewed Billy's medical history before prescribing an antibiotic to treat Billy. He noted that Billy had developed a rash when treated with penicillin for otitis media when he was two years old. 11. What antibiotic would you recommend for Billy? 12. What symptomatic therapy would be appropriate? 13. How would you stop this outbreak from spreading further? Otitis media - Inflammation of the middle ear.
Adi S.
Fill in the Blank. Blood agar contains many unspecified nutrients, supports the growth of a large number of bacteria, and allows differentiation of bacteria according to hemolysis (breakdown of blood). The medium is ________ and ________.
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