Textbook Question
What is the purpose of a counterstain in the acid-fast stain?
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Ch. 3 - Observing Microorganisms Through a Microscope
Tortora14th EditionMicrobiology: An IntroductionISBN: 9780138200398
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Table of contents
- Ch. 1 - The Microbial World and You18
- Ch. 2 - Chemical Principles20
- Ch. 3 - Observing Microorganisms Through a Microscope18
- Ch. 4 - Functional Anatomy of Prokaryotic and Eukaryotic Cells21
- Ch. 5 - Microbial Metabolism20
- Ch. 6 - Microbial Growth20
- Ch. 7 - The Control of Microbial Growth20
- Ch. 8 - Microbial Genetics19
- Ch. 9 - Biotechnology & DNA Technology20
- Ch. 10 - Classification of Microorganisms15
- Ch. 11 - The Prokaryotes: Domains Bacteria and Archaea14
- Ch. 12 - The Eukaryotes: Fungi, Algae, Protozoa, and Helminths17
- Ch. 13 - Viruses, Viroids, and Prions20
- Ch. 14 - Principles of Disease and Epidemiology21
- Ch. 15 - Microbial Mechanisms of Pathogenicity19
- Ch. 16 - Innate Immunity: Nonspecific Defenses of the Host20
- Ch. 17 - Adaptive Immunity: Specific Defenses of the Host20
- Ch. 18 - Practical Applications of Immunology20
- Ch. 19 - Disorders Associated with the Immune System19
- Ch. 20 - Antimicrobial Drugs19
- Ch. 21 - Microbial Diseases of the Skin and Eyes21
- Ch. 22 - Microbial Diseases of the Nervous System19
- Ch. 23 - Microbial Diseases of the Cardiovascular and Lymphatic Systems20
- Ch. 24 - Microbial Diseases of the Respiratory System20
- Ch. 25 - Microbial Diseases of the Digestive System20
- Ch. 26 - Microbial Diseases of the Urinary and Reproductive Systems19
- Ch. 27 - Environmental Microbiology20
- Ch. 28 - Applied and Industrial Microbiology19
Tortora14th EditionMicrobiology: An IntroductionISBN: 9780138200398Not the one you use?Change textbook
Chapter 3, Problem 6
Which of the following pairs is mismatched?
a. Capsule—negative stain
b. Cell arrangement—simple stain
c. Cell size—negative stain
d. Gram stain—bacterial identification
e. None of the above
Verified step by step guidance1
Step 1: Understand the purpose of each staining technique mentioned in the options. For example, a negative stain is used to visualize capsules and cell size by staining the background, leaving the cells or capsules clear.
Step 2: Analyze option (a): 'capsule—negative stain'. Since negative staining highlights capsules by staining the background and leaving the capsule unstained, this pair is correctly matched.
Step 3: Analyze option (b): 'cell arrangement—simple stain'. Simple stains color the cells uniformly, which helps in observing cell shape and arrangement, so this pair is also correctly matched.
Step 4: Analyze option (c): 'cell size—negative stain'. Negative staining is indeed used to observe cell size because it does not shrink or distort cells, so this pair is correctly matched as well.
Step 5: Analyze option (d): 'Gram stain—bacterial identification'. Gram staining differentiates bacteria into Gram-positive and Gram-negative groups, which is a fundamental step in bacterial identification, so this pair is correctly matched. Therefore, if all pairs are correctly matched, the answer would be (e) none of the above.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Negative Stain Technique
Negative staining uses acidic dyes that stain the background but not the cells, highlighting structures like capsules and cell size without heat-fixing. It is useful for observing delicate structures and true cell morphology.
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02:10
Introduction to Staining
Simple Stain and Cell Arrangement
Simple staining employs a single basic dye to color cells, enhancing contrast to observe cell shape and arrangement. It helps identify how bacterial cells group together, such as chains or clusters.
Recommended video:
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03:23Simple Staining
Gram Stain and Bacterial Identification
The Gram stain differentiates bacteria into Gram-positive or Gram-negative based on cell wall properties. This differential staining is fundamental for bacterial classification and guides identification and treatment.
Recommended video:
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04:57Gram Stain
Related Practice
Textbook Question
Why is a mordant used in the Gram stain? In the flagella stain?
Textbook Question
The maximum magnification of a compound microscope is (a) ________; that of an electron microscope, (b) ________. The maximum resolution of a compound microscope is (c) ________; that of an electron microscope, (d) ________. One advantage of a scanning electron microscope over a transmission electron microscope is (e) ________.
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Textbook Question
Assume that you are viewing a Gram-stained field of red cocci and blue rods through the microscope. You can safely conclude that you have
a. Made a mistake in staining
b. Two different species
c. Old bacterial cells
d. Young bacterial cells
e. None of the above
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Textbook Question
Which of the following is not a functionally analogous pair of stains?
a. Nigrosin and malachite green
b. Crystal violet and carbolfuchsin
c. Safranin and methylene blue
d. Ethanol-acetone and acid-alcohol
e. All of the above pairs are functionally analogous.
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Textbook Question
Assume you stain Clostridium by applying a basic stain, carbolfuchsin, with heat, decolorizing with acid-alcohol, and counterstaining with an acidic stain, nigrosin. Through the microscope, the endospores are 1, and the cells are stained 2.
a. 1—red; 2—black
b. 1—black; 2—colorless
c. 1—colorless; 2—black
d. 1—red; 2—colorless
e. 1—black; 2—red
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