Microbiology Lab Practical Exam 1
Questions and Answers Already Passed
What is the purpose of using a streak plate method?
✔✔To isolate individual bacterial colonies.
What is the morphology of cocci bacteria?
✔✔Spherical.
What is the function of the condenser on a microscope?
✔✔To focus light onto the specimen.
What is the name of the stain used in an acid-fast staining procedure?
✔✔Carbol fuchsin.
How do you test for motility in a bacterial sample?
✔✔Using a semi-solid agar stab or wet mount preparation.
1
,What is a colony-forming unit (CFU)?
✔✔A single microorganism that grows into a visible colony.
What type of media is MacConkey agar?
✔✔Selective and differential.
What is the purpose of using a control organism during staining procedures?
✔✔To validate the accuracy of the staining results.
What is the appearance of a positive result in a catalase test?
✔✔The production of bubbles when hydrogen peroxide is added.
What is the role of ethanol in a Gram stain procedure?
✔✔To act as a decolorizing agent.
What is the name of the counterstain used in Gram staining?
✔✔Safranin.
2
, What type of bacteria are identified using the oxidase test?
✔✔Bacteria with cytochrome c oxidase.
What is the primary purpose of aseptic technique in a microbiology lab?
✔✔To prevent contamination of samples and the environment.
What is the function of immersion oil when using a microscope?
✔✔To increase the resolution by reducing light refraction.
What is the first step in preparing a bacterial smear for staining?
✔✔Adding a small drop of water to the slide and mixing it with the bacteria.
What is the purpose of using a heat fix during slide preparation?
✔✔To adhere the bacteria to the slide and kill them.
What color do Gram-positive bacteria appear after Gram staining?
✔✔Purple.
3
Questions and Answers Already Passed
What is the purpose of using a streak plate method?
✔✔To isolate individual bacterial colonies.
What is the morphology of cocci bacteria?
✔✔Spherical.
What is the function of the condenser on a microscope?
✔✔To focus light onto the specimen.
What is the name of the stain used in an acid-fast staining procedure?
✔✔Carbol fuchsin.
How do you test for motility in a bacterial sample?
✔✔Using a semi-solid agar stab or wet mount preparation.
1
,What is a colony-forming unit (CFU)?
✔✔A single microorganism that grows into a visible colony.
What type of media is MacConkey agar?
✔✔Selective and differential.
What is the purpose of using a control organism during staining procedures?
✔✔To validate the accuracy of the staining results.
What is the appearance of a positive result in a catalase test?
✔✔The production of bubbles when hydrogen peroxide is added.
What is the role of ethanol in a Gram stain procedure?
✔✔To act as a decolorizing agent.
What is the name of the counterstain used in Gram staining?
✔✔Safranin.
2
, What type of bacteria are identified using the oxidase test?
✔✔Bacteria with cytochrome c oxidase.
What is the primary purpose of aseptic technique in a microbiology lab?
✔✔To prevent contamination of samples and the environment.
What is the function of immersion oil when using a microscope?
✔✔To increase the resolution by reducing light refraction.
What is the first step in preparing a bacterial smear for staining?
✔✔Adding a small drop of water to the slide and mixing it with the bacteria.
What is the purpose of using a heat fix during slide preparation?
✔✔To adhere the bacteria to the slide and kill them.
What color do Gram-positive bacteria appear after Gram staining?
✔✔Purple.
3
