gram - and gram +

• what colour is gram -

  pink
• what colour is gram +

  purple
• what does gram - contain?

  2 phospholid bilayers and 2 membranes that penicillin can not penetrate
• what do gram + contain?

  thicker layers of peptidoglycan meaning a thicker looking cell wall
• what can penicillin easily penetrate?

  gram +