51. In which of the following, lipo-polysaccharide is a major constituent of outer membrane of the cellwall?

A. Gram-positive bacteria
B. Gram-negative bacteria
C. Fungi
D. None of these

52. Which of the following structure(s) is /are external to cell wall?

A. Flagella
B. Stalks
C. Sheath
D. All of these

53. Which of the following may be most likely to be missing from a gram-positive bacterium?

A. Penicillin-binding protein
B. Peptidoglycan
C. Lipopolysaccharide
D. Phospholipid bilayer membrane