Which characteristic is typical of Gram-negative bacteria?

The characteristic that is typical of Gram-negative bacteria is that they contain an outer membrane with lipopolysaccharides. This structure is an essential feature of Gram-negative bacteria, distinguishing them from Gram-positive bacteria, which have a much thicker peptidoglycan layer and lack an outer membrane.

The outer membrane of Gram-negative bacteria serves as an additional barrier, providing protection against certain antibiotics and contributing to the bacteria's overall structural integrity. Lipopolysaccharides (LPS) are important components of this outer membrane and play a crucial role in the immune response. When Gram-negative bacteria are lysed, they can release LPS, which may trigger strong inflammatory responses in hosts.

Understanding the role of the outer membrane and lipopolysaccharides helps to explain the broader implications of Gram-negative bacteria in medical microbiology, particularly their resistance to antibiotics and their role as potential pathogens.