You are a third-year medical student working with Infectious Disease and are presented with a Gram-staining for a patient, showing a pink rod-shaped bacteria. The physician you are working with lists some of the characteristics of Gram-positive and negative bacteria. Which of the following would NOT be a characteristic of the bacteria observed on the Gram stain

Cytoplasmic membrane

Periplasmic space

Thick peptidoglycan layer

Lipoproteins