Podcast
Questions and Answers
What is the reason behind gram-positive bacteria appearing purple after the Gram stain test?
What is the reason behind gram-positive bacteria appearing purple after the Gram stain test?
- They retain the crystal violet stain due to their thick peptidoglycan layer (correct)
- They have a thinner peptidoglycan layer that retains the crystal violet stain
- They have an outer membrane that retains the crystal violet stain
- They take up the counterstain (safranin or fuchsine) and appear red or pink
Why do gram-negative bacteria appear red or pink after the Gram stain test?
Why do gram-negative bacteria appear red or pink after the Gram stain test?
- They have an outer membrane that retains the crystal violet stain
- They retain the counterstain (safranin or fuchsine) and appear red or pink (correct)
- They cannot retain the crystal violet stain due to their thin peptidoglycan layer
- They have a thicker peptidoglycan layer that retains the crystal violet stain
What effect does alcohol have on gram-negative bacteria during the decolorization stage of the Gram stain test?
What effect does alcohol have on gram-negative bacteria during the decolorization stage of the Gram stain test?
- It degrades the outer membrane, making the cell wall more porous (correct)
- It causes them to retain the crystal violet stain
- It thickens their peptidoglycan layer
- It makes them appear red or pink
What is the main difference in cell wall structure between gram-positive and gram-negative bacteria?
What is the main difference in cell wall structure between gram-positive and gram-negative bacteria?
Why are gram-positive bacteria more receptive to certain cell wall–targeting antibiotics than gram-negative bacteria?
Why are gram-positive bacteria more receptive to certain cell wall–targeting antibiotics than gram-negative bacteria?
Flashcards
Why are gram-positive bacteria purple after a Gram stain?
Why are gram-positive bacteria purple after a Gram stain?
They retain the crystal violet stain due to their thick peptidoglycan layer.
Why are gram-negative bacteria red/pink after a Gram stain?
Why are gram-negative bacteria red/pink after a Gram stain?
They retain the counterstain (safranin or fuchsine) and appear red or pink.
What does alcohol do to gram-negative bacteria in Gram staining?
What does alcohol do to gram-negative bacteria in Gram staining?
It degrades the outer membrane, making the cell wall more porous.
Main cell wall difference between gram-positive and gram-negative?
Main cell wall difference between gram-positive and gram-negative?
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Why are gram-positive bacteria more susceptible to cell wall antibiotics?
Why are gram-positive bacteria more susceptible to cell wall antibiotics?
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