What is Gram staining?
Q: What is Gram staining?
A: Gram staining is a method of classifying bacteria into two large groups: gram-positive and gram-negative.
Q: Who invented Gram staining?
A: Gram staining was invented by Hans Christian Gram.
Q: How does Gram staining work?
A: Gram staining stains bacteria according to the chemical and physical properties of their cell walls. A violet dye is put on the bacteria, which stains peptidoglycan, a thick layer found only in gram-positive bacteria. After the first stain, another stain (usually safranin or fuchsin) gives all gram-negative bacteria a red or pink color.
Q: Why is the Gram stain important?
A: The Gram stain is important because it is almost always the first step in the identification of a bacterial organism.
Q: Can all bacteria be classified by Gram staining?
A: No, not all bacteria can be classified by Gram staining. Bacteria for which the method does not work are called 'gram-variable' or 'gram-indeterminate'.
Q: What did Gram use the Gram stain for initially?
A: Gram used the Gram stain to make bacteria in the lungs easier to see.
Q: When was the Gram stain method published?
A: The Gram stain method was published by Gram in 1884.
