The cell envelope of Mycobacterium sp is unlike the envelope

Solution

Mycobacterium sp have a cell envelope different from other bacteria. It is peculiar in having Mycolic acids in the cell wall. It is a wwaxy substance which preevnts the penetration of stains. For it to be penetrated, stains should be heated.

Based on 16s RNA comparison, Mycobacteria are closely related to Gram Positive bacteria with high G+C content like Bacillus subtilis. A genome tree constructed based on conserved gene content, M. tuberculosis is more related to Gram-negative than to Gram-positive bacteria as reflected by the evolutionary distance between nearest ancestral units. This is also supported by another fact that Mycobacteria shares relatively more orthologous genes for energy production and conversion with Gram-negative bacteria like E.coli.