Biomedical Engineer Question:

This method is used to identify bacterial species into two communities i.e. Gram positive and gram negative. This method is based on chemical and physical properties of their cell walls. It can be used to detect peptidoglycan, which is present in a thick layer in Gram positive bacteria. Purple/blue colour refers to the gram positive bacteria. Red colour stain refers to the gram negative bacteria. This method is very popularly used in the identification of bacterial organism.