1. What are the principles of the various sterilization methods?

Question

2. What is the relative merits of the pour-plate method as compared with streak-plate method for the isolation of bacteria?
3. What are methods that I can use to obtain a pure culture and what's the significance?
4. What are the differences between lawn culture and pour plate techniques?

Answer 1

1. Autoclaving materials (intense heat and pressure) should sterilize any media or glassware. 10% bleach , then 70% EtOH is used to wipe counterspace. Flame sterilization can occur with prior dipping in 95%EtOH (spreader) or not
(loop). If you are in a hood, you can also sterilize with UV light. In all these situations, the intense heat/chemical conditions will denature proteins/disrupt chemical bonds. Flaming the opening of a (glass) bottle will create an updraft and prevent microbes in the air from falling into the bottle.
2. With a pour plate, you don't need to prep plates ahead of time and it's easier to visualize/measure how many microbes per volume or mass sample.
3. To obtain a pure culture, grow a lawn and select desired colony. Streak a plate with the one colony and incubate under sterile conditions. Use selective media as applicable.
4. In a pour plate, the bacteria are mixed with the (warm liquid) nutrient agar before it solidifies. A lawn culture is inoculated on the agar surface (after it solidifies).

Answer 2

Principles of vaious sterilization methods- 1.dry heat (as in oven), 2.moist air (steam and boiling ) 3. Moist air under pressure (autoclaving) 4. ultraviolet rays 5. chemical disifectants (alcohol, bleach, 6. direct heat (flame).

Merits of Pour Plate vs Streak plate- Pour plate is used for quantifying bacteria. treak plate is the most commonly used qualifying method of isolation.

Obtaining Pure culture- 1. Use of culture media that supports regular growth SBE (sheep blood agar ) 2. Differential media that will allow certain bacteria to flourish over others (McConkeys, Salmonella- Shigella plates, inoculating deep tube media for anaerobic prefering bacteria, specialized media to grow special microorganisms (Sabourauds, Bordetella etc)

Answer 3

Principle Of Pour Plate Method

Answer 4

I hated microbiology.

With a streak plate it will grow isolated colonies

Answer 5

Broadly sterilizations are as heat, chemical and filteration methods of sterilization. You can find complete details below

Answer 6

kill germs

Answer 7

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