Question

What does gram-negative bacteria produce that gram-positive bacteria don't?

A) Gram-negative bacteria produce lipopolysaccharides (LPS), forming the outer layer of the cell membrane.
B) Gram-negative bacteria produce peptidoglycan, providing structural support to the cell wall.
C) Gram-negative bacteria produce exotoxins, potent proteins that damage host cells.
D) Gram-negative bacteria produce capsule polysaccharides, enhancing resistance against immune responses.

Answer 1

Gram-negative bacteria produce lipopolysaccharides (LPS) in their outer membrane, which Gram-positive bacteria do not have. LPS functions as an endotoxin and is significant in the identification of bacterial strains.

Step-by-step explanation:

Gram-negative bacteria produce lipopolysaccharides (LPS), forming the outer layer of the cell membrane.

Unlike Gram-positive bacteria, which have a thick peptidoglycan layer and are anchored to the cell membrane by lipoteichoic acids, Gram-negative bacteria have a comparatively thin peptidoglycan layer. The distinctive feature of Gram-negative bacteria is the additional outer membrane containing lipopolysaccharides (LPS) and lipoproteins. The presence of LPS is significant because it functions as an endotoxin, which can induce a strong immune response in humans, resulting in symptoms like fever and septic shock. The LPS is composed of Lipid A, a core polysaccharide, and an O side chain that varies among species and strains, leading to the identification of specific pathogenic strains through serological tests.

Gram-negative bacteria produce lipopolysaccharides (LPS), forming the outer layer of the cell membrane. This outer membrane is attached to the peptidoglycan layer and contains the molecule LPS, which functions as an endotoxin in infections involving gram-negative bacteria. Gram-positive bacteria, on the other hand, do not have an outer membrane or produce LPS.