1
Q
What dye is used for negative stains?
A
Acid dye nigrosin, it has negative charge chromophores
2
Q
Will the cells remain unstained and have a dark coloured background in the negative stain experiment?
A
Yes
3
Q
Why can’t methylene blue be used in place of nigrosin for negative stain?
A
methylene blue is a basic stain and it will adhere to the slightly negative bacteria
-> Nigrosin is an acidic stain
4
Q
What are the practical advantages of negative staining?
A
cells will retain their natural sizes and shape, therefore, not distorted by heat
5
Q
Why doesn’t nigrosin penetrate bacterial cells?
A
because it is negatively charged
BIO 240L
flashcards
Decks in class (29)
# Cards
-
SIMPLE STAINING EXP 112
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HOW TO USE A MICROSCOPE10
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BASIC BACTERIAL SHAPES4
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THE GRAM STAIN8
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ACID FAST STAIN11
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SPORE STAIN (BARTHOLOMEW AND MITTWER COLD STAIN)5
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NEGATIVE STAIN5
-
CAPSULE STAIN7
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SELECTIVE, DIFFERENTIAL, AND ENRICHED MEDIA19
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STREAK-PLATE METHOD - ISOLATION OF PURE CULTURES7
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THE POUR PLATE METHOD4
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CULTURE MEDIA STERILIZATION8
-
PLATE COUNT METHOD5
-
DEMONSTRATION OF MOTILITY9
-
BACTERIAL FLAGELLA11
-
NUTRITION OF MICROORGANISMS8
-
ANALYSIS OF PLASMID AND GENOMIC DNA BY AGAROSE GEL20
-
SOME METABOLIC ACTIVITIES OF BACTERIA26
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BACTERIAL ENZYMES29
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EFFECT OF TEMPERATURE ON MICROBIAL GROWTH13
-
pH and MICROBIAL GROWTH7
-
OXYGEN REQUIREMENTS OF MICROORGANISMS17
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EFFECT OF ULTRAVIOLET RADIATION ON MICROORGANISMS13
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LETHAL EFFECTS OF TEMPERATURE10
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EFFECT OF OSMOTIC PRESSURE ON MICROBIAL GROWTH16
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OLIGODYNAMIC ACTION9
-
EVALUATION OF CHEMICAL ANTIMICROBIAL AGENTS9
-
ANTIBIOTIC SENSITIVITY TESTING11
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ISOLATION OF BACTERIAL MUTANTS8
