Gram positive bacteria

Answer 1

In 1884 the Danish physician Chriastan Gram developed the stain known as Gram stain with which one can distinguish the two cells of bacteria which is based on the difference of their cell wall. The gram positive cell stained purple whereas gram negative stained pink or red by gram staining. This is due to because gram positive bacteria cell wall consist of single 20-80 nm thick homogenous layer of peptidoglycan(murein)lying outside the plasma membrane. In contrast the gram negative cell wall is quite complex. It has a 2-7 nm peptidoglycan layer covered by a 7-8 nm thick outer membrane.

Answer 2

Gram positive bacteria have a thick layer of peptidoglycan in their cell walls that retains the crystal violet stain during the Gram staining process. This gives them a purple color under the microscope. Examples include Staphylococcus and Streptococcus species.