Final answer:
Gram classification of bacteria is based on cell wall and outer membrane differences, with Gram-positive bacteria having a thick, peptidoglycan and teichoic acid-based wall and Gram-negative bacteria having a thinner, outer envelope.
Step-by-step explanation:
Gram classification in microbiology is based on the characteristics of bacterial cell walls. The Gram staining technique, developed by the Dan*ish bacteriologist Hans Christian Gram in 1884, is a crucial method for differentiating bacterial species into two groups: Gram-positive and Gram-negative.
This classification relies on the ability of bacterial cells to retain or lose a violet dye during the staining process. Gram-positive bacteria retain the dye, appearing violet under a microscope, while Gram-negative bacteria do not, appearing red or pink.
The key difference is in the composition of the cell wall, with Gram-positive bacteria having a thick peptidoglycan layer, and Gram-negative bacteria having a thinner peptidoglycan layer surrounded by an outer membrane.