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n experiment #13, what two problems do we encounter when we try to stain a bac 1

ID: 207392 • Letter: N

Question

n experiment #13, what two problems do we encounter when we try to stain a bac 1- I cterium with a capsule using ordinary staining techniques? What is the purpose of the India ink used? 2. What is an endospore? What two species of bacteria produce endospores? How are endospores destroyed? 3- Which of the following is an acid fast microorganism? a) E. coli b) S. aureus c) S. pneumonia d) Mycobacterium smegmatis 4 What is the difference between complex and defined medium? What is the advantage of using defined media to grow a fastidious organism? 5- What is a differential medium? 6- To destroy all spores by heating, Microbiology experts recommend a temperature of 121 C and 15 psi of pressure for 15 to 20 minutes. Which type of sterilizing technique best accomplishes this task? a) Autoclaving b) using a Dry oven c) Filtering by vacuunm d) Boiling

Explanation / Answer

1-(datainsufficient)

INDIA INK along

with other stains used to determine if a cell has gelatinous capsule.It is used in clinical microbiology lab is to confirm the morphology of encapsulated yeast Cryptococcus spp. which cause cryptococcal meningitis.

2-Endospores are hard, defensive structures that enable some bacteria to survive harmful environmental conditions, such as starvation, high temperatures, desiccation , chemical disinfectants and extremes in pH.

Bacillus, the members of which are aerobic sporeformers in the soils, and Clostridium, whose species are anaerobic sporeformers of soils, sediments and the intestinal tracts of animals are used to produce endosperm.

endospores can be destroyed by burning or by autoclaving at a temperature exceeding the boiling point of water, 100 °C.

3-mycobacterium contains large amount of lipid substance within their cell walls called mycolic acid,these acids resist staining by ordinary methods such as gram stain.

4-Complex media- that is, media for which the exact chemical composition varies slightly from batch to batch.

Defined media- a medium whose exact chemical composition is known.

fastidious organism

have simple enzyme systems therefore must have many organic molecules,rowth factors. Can't make their own food very well. so defined media is used to make their food.

5-Differential medium are used to

distinguishes between different types of microbes.it can grow more than one microorganism, but depending on how each organism reacts to the media (like turns red) it differentiates from another microorganism

6-A