Members of the Deinococcus genus present an interesting conundrum to scientists who try to classify them as either gram-positive or gram-negative. Deinococcus has a thick layer of peptidoglycan and also an outer membrane. Explain why these features complicate its classification

Bacteria can be classified traditionally into two broad categories according to their cell wall, which are Gram-positive bacteria and Gram-negitive bacteria.

Gram-positive bacteria are bacteria that produce a positive result when Gram stain test is performed. It takes up the crystal violet stain of the test, and then show a purple-coloured appearance when seen through an optical microscope. This is as a result of the thick "peptidoglycan" layer in the bacterial cell wall which retains the stain used in the cell after washing it away from the rest of the sample.

Gram-negative bacteria after the decolorization don't retain the violet stain, the outer membrane of gram-negative cells is degraded by the alcohol. The peptidoglycan layer is positioned and between the membrane and a bacterial outer membrane, causing them to take up the counterstain and made appear red or pink.

Therefore, Deinococcus is one genus of the bacterial phylum that have resistant to environmental hazards. They posses thick cell walls that give them Gram-positive stains, but they also posess second membrane that made them them closer in structure to Gram-negative bacteria, which present an interesting conundrum to scientists who try to classify them as either gram-positive or gram-negative.