Microbiology Lab Practical 1 Latest
Version Graded A+
What is the purpose of using immersion oil with a 100x objective lens?
✔✔To reduce light refraction and improve resolution.
What is the correct way to sterilize an inoculating loop before use?
✔✔Heat it in the flame of a Bunsen burner until it glows red.
What is the main purpose of a simple stain?
✔✔To visualize the shape and arrangement of bacteria.
What is the purpose of a negative stain?
✔✔To observe the morphology and size of bacteria without heat fixation.
What color do Gram-positive bacteria appear after a Gram stain?
✔✔Purple.
1
,What is the decolorizing agent used in the Gram staining process?
✔✔Alcohol or acetone.
What type of microorganism is visualized with an acid-fast stain?
✔✔Mycobacteria.
What is the purpose of performing a streak plate technique?
✔✔To isolate individual bacterial colonies.
What is a colony in microbiology?
✔✔A visible mass of microorganisms originating from a single cell.
What is the function of a condenser in a compound microscope?
✔✔To focus light onto the specimen.
What is the magnification of the ocular lens in most standard microscopes?
✔✔10x.
2
,What is the term for the ability of a microscope to distinguish two closely spaced objects as
separate?
✔✔Resolution.
What is the purpose of heat fixation in bacterial smear preparation?
✔✔To kill the bacteria and adhere them to the slide.
What type of media is used to distinguish between microorganisms based on biochemical
properties?
✔✔Differential media.
What is the purpose of a motility test in microbiology?
✔✔To determine if an organism is capable of movement.
What structure allows bacterial motility?
✔✔Flagella.
What is the purpose of a selective medium?
3
, ✔✔To inhibit the growth of certain organisms while allowing others to grow.
What does a positive catalase test indicate?
✔✔The presence of the enzyme catalase in the organism.
What is the purpose of using a control in microbiology experiments?
✔✔To provide a standard for comparison and ensure accuracy.
What is the term for bacteria that can grow at high salt concentrations?
✔✔Halophiles.
What is the primary component of bacterial cell walls that Gram staining detects?
✔✔Peptidoglycan.
What color do acid-fast bacteria appear after staining?
✔✔Pink or red.
What is the purpose of incubating plates upside down?
4
Version Graded A+
What is the purpose of using immersion oil with a 100x objective lens?
✔✔To reduce light refraction and improve resolution.
What is the correct way to sterilize an inoculating loop before use?
✔✔Heat it in the flame of a Bunsen burner until it glows red.
What is the main purpose of a simple stain?
✔✔To visualize the shape and arrangement of bacteria.
What is the purpose of a negative stain?
✔✔To observe the morphology and size of bacteria without heat fixation.
What color do Gram-positive bacteria appear after a Gram stain?
✔✔Purple.
1
,What is the decolorizing agent used in the Gram staining process?
✔✔Alcohol or acetone.
What type of microorganism is visualized with an acid-fast stain?
✔✔Mycobacteria.
What is the purpose of performing a streak plate technique?
✔✔To isolate individual bacterial colonies.
What is a colony in microbiology?
✔✔A visible mass of microorganisms originating from a single cell.
What is the function of a condenser in a compound microscope?
✔✔To focus light onto the specimen.
What is the magnification of the ocular lens in most standard microscopes?
✔✔10x.
2
,What is the term for the ability of a microscope to distinguish two closely spaced objects as
separate?
✔✔Resolution.
What is the purpose of heat fixation in bacterial smear preparation?
✔✔To kill the bacteria and adhere them to the slide.
What type of media is used to distinguish between microorganisms based on biochemical
properties?
✔✔Differential media.
What is the purpose of a motility test in microbiology?
✔✔To determine if an organism is capable of movement.
What structure allows bacterial motility?
✔✔Flagella.
What is the purpose of a selective medium?
3
, ✔✔To inhibit the growth of certain organisms while allowing others to grow.
What does a positive catalase test indicate?
✔✔The presence of the enzyme catalase in the organism.
What is the purpose of using a control in microbiology experiments?
✔✔To provide a standard for comparison and ensure accuracy.
What is the term for bacteria that can grow at high salt concentrations?
✔✔Halophiles.
What is the primary component of bacterial cell walls that Gram staining detects?
✔✔Peptidoglycan.
What color do acid-fast bacteria appear after staining?
✔✔Pink or red.
What is the purpose of incubating plates upside down?
4
