Which of the following statements about the outer membrane of Gram-negative cell wall is FALSE?
A. The outside leaflet is largely composed of lipopolysaccharides.
B. The outer membrane contains porins that allow passage of molecules and ions directly into the periplasmic space.
C. The outer membrane acts as a protective barrier to many toxic compounds.
D. The lipid A part of the lipopolysaccharide molecule is toxic to humans.
E. None of these choices are correct.
To determine which statement about the outer membrane of the Gram-negative cell wall is FALSE, we need to evaluate each statement individually.
Statement A: The outside leaflet of the outer membrane is largely composed of lipopolysaccharides. This statement is TRUE. Lipopolysaccharides (LPS) are major components of the outer membrane in Gram-negative bacteria, covering the surface of the cell.
Statement B: The outer membrane contains porins that allow the passage of molecules and ions directly into the periplasmic space. This statement is TRUE. Porins are protein channels present in the outer membrane that allow the diffusion of small molecules and ions.
Statement C: The outer membrane acts as a protective barrier to many toxic compounds. This statement is TRUE. The outer membrane acts as a barrier, preventing the entry of various toxic compounds, including antibiotics and chemicals.
Statement D: The lipid A part of the lipopolysaccharide molecule is toxic to humans. This statement is TRUE. Lipid A is the toxic component of the LPS molecule and can cause severe immune responses in humans.
Since all the statements are TRUE, the answer to the question is E. None of these choices are correct.