What is the definition of medium in microbiology?
The medium supports the growth of the microorganism
Medium is essential for culturing microorganisms.
Name the types of medium and provide examples.
- Solid medium: Nutrient agar plates (NA plates)
- Liquid medium: Nutrient broth (NA broth) contained in tubes or chicken eggs
Different media are used for various types of microbial growth.
What are the tools used for transferring microorganisms?
- Loop
- Needle
- Swab
- Syringe
- Slide
These tools are essential for handling and transferring microbial samples.
What are the tests used for gathering information about microorganisms?
- Biochemical tests
- Drug sensitivity tests
- Genetic typing (DNA analysis)
- Immunological tests
These tests help in identifying and characterizing microorganisms.
What are the key characteristics of a microscope?
- Magnification: Ability to enlarge objects
- Resolving power: Capacity to distinguish or separate two adjacent objects
Resolution depends on the wavelength of light and the characteristics of the objectives.
List the parts of a microscope.
- Ocular lens
- Resolving nose
- Objective lenses (scanning, low, high power)
- Mechanical stage
- Base
- Arm
- Light (normal white light)
Each part plays a crucial role in the functioning of the microscope.
How do you calculate the total magnification of a microscope?
Objective power multiplied by ocular power
Examples: Scanning 4x10=40, low power 10x10=100, high power 40x10=400, oil immersion 10x100=1000.
What are the uses of wet mounts and hanging drop mounts?
- Examine characteristics of live cells
- Assess size
- Determine motility
- Identify shape and arrangement
These methods allow observation of living microorganisms.
What are the methods used for fixation of samples on a glass slide?
- Drying
- Heating
- Using alcohol or serum
Fixation preserves the structure of the microorganisms for observation.
What are examples of positive stains?
- Basic or cationic dyes
- Methylene blue
- Crystal violet
- Methyl red
- Safranin
Positive stains are used to color the cells for better visibility.
What is negative staining and what are its examples?
- Uses acidic dyes or anionic dyes
- Examples: India Ink, Nigrosine
Negative staining helps in visualizing the morphology of cells.
What are examples of differential stains?
- Gram stain
- Acid-fast stain
Differential stains help differentiate between different types of bacteria.
What are examples of structural stains?
- Capsular stain
- Flagella stain
Structural stains highlight specific structures within the microorganisms.
What are the six I’s in microbiology?
- Culture
- Inoculation
- Isolation
- Incubation
- Inspection
- Identification
These steps are crucial for studying microorganisms.
What are the techniques used for isolating microorganisms?
- Streaking plate method
- Pour plate method
- Spread plate method
These methods are used to obtain isolated colonies from mixed cultures.
Define contaminated culture, mixed culture, and pure cultures.
- Contaminated culture: Contains unwanted microorganisms
- Mixed culture: Contains two or more different species
- Pure culture: Contains only one species
Understanding these definitions is essential for microbiological studies.
What are the definitions of synthetic media, complex media, general purpose media, and enriched media?
- Synthetic media: Chemically defined
- Complex media: Nutrient-rich but not chemically defined
- General purpose media: Supports a wide range of microorganisms
- Enriched media: Contains additional nutrients for specific organisms
These media types are used based on the nutritional requirements of the microorganisms.
What should you refer to for identifying agents that make media selective or differential?
Media table file on Moodle
Check table 2 and 3 middle row for identifying these agents.
