Question

• 7. This image shows results of a(n) stain: A. Spore; B. Acid Fast; C. Gram; D. Capsule 8. is the primary stain for this procedure. 9. Identify the organisms shown as to staining reaction and morphology.

Answer 1

7c. Gram

The Gram stain is a differential method of staining used to assign bacteria to one of two groups (gram-positive and gram-negative) based on the properties of their cell walls.

8. The primary stain of Gram's method is crystal violet. Gram-positive retain bluish-purple colour whereas Gram-negative strain becomes red in colour after applying secondary stain i,.e safranin.

9. As the diagram shown in the question shows bacteria that have stained bluish colour so they are Gram-positive and are spherical in shape or morphology hence they are Gram-positive Cocci. Gram-positive bacteria stain violet due to the presence of a thick layer of peptidoglycan in their cell walls, which retains the crystal violet these cells are stained with.