Gram Staining Quiz

What is the key structural difference exploited in Gram staining?

• DNA content

• Peptidoglycan layer

• Ribosome size

• Flagella presence

Which type of bacteria has a thick peptidoglycan layer?

• Gram-negative

• Gram-positive

• Acid-fast

• Spirochetes

What is the primary stain used in Gram staining?

• Safranin

• Methylene blue

• Crystal violet

• Carbol fuchsin

What is the purpose of the decolorization step in Gram staining?

• To fix the cells to the slide

• To selectively remove the crystal violet from certain cells

• To stain the cells red

• To enhance cell visibility

Which type of bacteria has an outer lipid membrane?

• Gram-positive

• Gram-negative

• Acid-fast

• Mycoplasma

What is the final color of Gram-positive bacteria after Gram staining?

• Red

• Blue

• Purple

• Green

What is the purpose of Gram staining in bacterial identification?

• To determine the shape of bacteria

• To classify bacteria as Gram-positive or Gram-negative

• To measure bacterial growth rate

• To identify bacterial DNA

What is the appearance of Gram-negative bacteria after Gram staining?

• Purple

• Blue

• Red or pink

• Colorless

What color do Gram-positive bacteria appear after Gram staining?

• Red

• Pink

• Purple

• Green

What is the purpose of safranin in the Gram staining process?

• Primary stain

• Mordant

• Decolorizer

• Counterstain