Unit 1 - Gram Pos + Neg Bacteria

Question 1

Gram Positive Bacteria

Answer 1

Has a THICK layer of PEPTIDOGLYCAN so they can hold in crystal violet dye. This is why it is PURPLE

Question 2

Gram Negative Bacteria

Answer 2

Has a VERY THIN layer, so it DOESN’T hold in the purple dye. They have to use a second stain of a different colour, so it is PINK