Why would epithelial cells more than likely gram stain negative?

Answer 1

Peptidoglycan is the protein found in gram positive bacteria which allows crystal violet (stain) to hold fast to the cell. This causes the gram positive coloration. Gram negative bacteria have little peptidoglycan in their cell walls so when the alcohol rinses the slide the blue coloration comes off.

Epithelial celld do not contain peptidoglycan so they will not stain positive. Hope this helps.

Answer 2

Because human cells do not have the thick proteoglycan layer that is found in gram + bacteria which traps the crystal violet stain and prevents it from being washed out of cells by alcohol.

Answer 3

I'm not positive.