Which color do Gram-positive bacteria stain after Gram staining?

Unlock all questions

This demo includes only 20 questions. Upgrade to access hundreds of questions, flashcards, exam simulations, and disable ads.

Full question bankExam simulationsFlashcards
From $24.99Unlock all

Study for the NBEO Microbiology exam. Prepare with flashcards and multiple choice questions, each with hints and explanations. Get ready for your exam!

Multiple Choice

Which color do Gram-positive bacteria stain after Gram staining?

Explanation:
Gram-positive bacteria stain purple after Gram staining because their thick peptidoglycan layer traps the crystal violet-iodine complex during the decolorization step. This prevents the dye from washing out, so the cells retain the purple color. In contrast, Gram-negative bacteria have a thinner peptidoglycan layer and an outer membrane that is disrupted by alcohol, allowing the crystal violet to wash out and the counterstain to color them pink. The other colors listed don’t appear in this method.

Gram-positive bacteria stain purple after Gram staining because their thick peptidoglycan layer traps the crystal violet-iodine complex during the decolorization step. This prevents the dye from washing out, so the cells retain the purple color. In contrast, Gram-negative bacteria have a thinner peptidoglycan layer and an outer membrane that is disrupted by alcohol, allowing the crystal violet to wash out and the counterstain to color them pink. The other colors listed don’t appear in this method.

More Multiple Choice Questions
Subscribe

Get the latest from Examzify

You can unsubscribe at any time. Read our privacy policy