Microbiology and Parasitology Laboratory: Gram Staining Activity

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What is the purpose of flooding the smear with Gram's Crystal Violet for 1 minute?

To counterstain with Safranin

To apply the decolorizer

To fix the bacterial suspension (correct)

To wash the slide

Why is it important to air dry or blot dry the slide between sheets of clean paper after counterstaining with Safranin?

To prevent the bacteria from spreading out on the slide

To remove excess Safranin dye (correct)

To enhance the color intensity of the stain

To fix the Safranin stain

What is the purpose of adding decolorizer (95% ethanol) drop-by-drop to the smear during the Gram staining process?

To fix the bacteria to the slide

To enhance the color of the stain

To remove excess crystal violet

To differentiate between Gram-positive and Gram-negative bacteria (correct)

What does spreading the bacterial suspension thin on the slide with a cover slip help achieve?

Allows for better observation under the microscope Signup and view all the answers

Why is it crucial to rinse the smear with distilled water after applying Gram's Iodine?

To prepare for counterstaining with Safranin Signup and view all the answers

Why should one examine the finished smear under HPO and take a picture as part of the Gram staining process?

To observe cellular arrangement Signup and view all the answers

What is the purpose of staining in microbiology?

To make bacterial cells easier to visualize Signup and view all the answers

What is the main difference between simple stains and differential stains?

Differential stains provide additional information about cell structure, while simple stains do not Signup and view all the answers

What is the primary stain used in the Gram staining method?

Crystal violet Signup and view all the answers

Why does peptidoglycan not dissolve in organic solvents during the Gram staining process?

It is nonpolar Signup and view all the answers

Which type of bacteria would appear purple after the Gram staining process?

Bacteria with thick cell walls composed primarily of peptidoglycan Signup and view all the answers

Which reagent in the Gram staining method acts as a mordant?

Gram's iodine Signup and view all the answers

What is the purpose of the malachite green staining procedure in microbiology?

To differentiate between vegetative cells and endospores Signup and view all the answers

Which type of bacteria retains the blue stain in the gram staining procedure?

Gram-positive bacteria Signup and view all the answers

What is the characteristic distinction between gram-positive and gram-negative bacteria?

Response to staining procedure Signup and view all the answers

Which type of bacteria is characterized by sometimes retaining and sometimes not retaining the blue color in gram staining?

Gram-variable bacteria Signup and view all the answers

What is a typical example of a gram-positive bacteria mentioned in the text?

Staphylococci producing boils Signup and view all the answers

What is one of the objectives of the mentioned activity in the text related to microbiology?

Differentiate gram-positive and gram-variable bacteria Signup and view all the answers

Which component of the cell wall is primarily affected by the decolorizer in the Gram staining process?

Lipid Signup and view all the answers

What is the purpose of the counterstain safranin in Gram staining?

To dye the colorless cells Signup and view all the answers

What color will Gram-positive cells appear after the Gram staining process?

Blue or purple Signup and view all the answers

What is released by Gram-negative cells when they die and contribute to fever and malaise?

Endotoxin Signup and view all the answers

How would rod-shaped, purple (blue) cells be reported after a Gram stain procedure?

Gram-positive bacilli Signup and view all the answers

What is the staining reaction displayed by cells that appear pink or red after a Gram stain procedure?

Gram-negative Signup and view all the answers

What is the purpose of a mordant in the gram staining procedure?

Fix the primary stain in the cell wall Signup and view all the answers

Why is it important to use a mordant in the gram staining process?

To differentiate between Gram-positive and Gram-negative bacteria Signup and view all the answers

Which step of the gram staining process involves the application of a mordant?

Application of iodine Signup and view all the answers

Why is counterstain used in the gram staining technique?

To visualize Gram-positive bacteria clearly Signup and view all the answers

Which part of the gram staining process ensures that Gram-positive bacteria retain the crystal violet stain?

Application of iodine as a mordant Signup and view all the answers

In gram staining, what would happen if a mordant was omitted from the process?

The color differentiation between bacteria types would not be clear Signup and view all the answers