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Questions and Answers
Which stain is used as the primary stain in Gram staining?
Which stain is used as the primary stain in Gram staining?
What color do Gram-positive bacteria appear after the Gram staining procedure?
What color do Gram-positive bacteria appear after the Gram staining procedure?
Which step in the Gram staining procedure involves the application of iodine?
Which step in the Gram staining procedure involves the application of iodine?
What is the primary purpose of the Gram staining method?
What is the primary purpose of the Gram staining method?
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What color do Gram-negative bacteria appear after the Gram staining procedure?
What color do Gram-negative bacteria appear after the Gram staining procedure?
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What is a characteristic of Gram-positive cell walls?
What is a characteristic of Gram-positive cell walls?
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What component is absent in Gram-positive bacteria but present in Gram-negative bacteria?
What component is absent in Gram-positive bacteria but present in Gram-negative bacteria?
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What is the chemical composition of Gram-negative bacteria's cell wall?
What is the chemical composition of Gram-negative bacteria's cell wall?
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Study Notes
Gram Staining Procedure and Differences Between Gram Positive and Gram Negative Bacteria
- The Gram staining method was developed by Danish Physician Christian Gram in 1884
- It is a differential staining procedure that classifies bacteria into two classes - Gram positive and Gram negative
- Gram positive bacteria retain crystal violet and appear dark violet, while Gram negative bacteria lose the crystal violet and appear red when counterstained by safranin
- Gram positive cell walls contain teichoic acid, teichuronic acid, and polysaccharide molecules
- Gram negative cell walls contain lipoprotein, outer membrane, and lipopolysaccharide
- Gram positive cell walls are thick layered (0.015 μm-0.02μm) and rigid due to the presence of peptidoglycans
- Gram negative cell walls are thin layered (0.0075μm–0.012μm) and elastic due to the presence of a lipoprotein-polysaccharide mixture
- The chemical composition of Gram positive bacteria is 80% peptidoglycans, 20% polysaccharide, and the presence of teichoic acid, while Gram negative bacteria contain 3 to 12% peptidoglycans and rest is polysaccharides and lipoproteins, with teichoic acid absent
- Gram negative bacteria have an outer membrane and periplasmic space, which are absent in Gram positive bacteria
- The differences between Gram positive and Gram negative bacteria are summarized in Table 1.6
- The Gram staining procedure involves specific steps, as illustrated in Figure 1.10
- This staining method is crucial for differentiating between the two types of bacteria based on their cell wall characteristics
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Description
Test your knowledge of the Gram staining procedure with this quiz. Explore questions about the primary stain used, the color of Gram-positive bacteria after staining, and the step involving the application of iodine. Perfect for microbiology students and enthusiasts.
