교과서 질문
When Legionella was newly discovered, why was it classified with the pseudomonads?
a. It is a pathogen.
b. It is an aerobic gram-negative rod.
c. It is difficult to culture.
d. It is found in water.
e. None of the above
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7. Prokaryotic Cell Structures & Functions
Gram-Negative Cell Walls
Multiple Choice
Which of the following statements accurately describes the gram-negative outer membrane?
A
It is primarily composed of thick peptidoglycan layers.
B
It lacks porin proteins and is impermeable to most molecules.
C
It contains lipopolysaccharides that contribute to the cell's antigenic properties.
D
It is found only in gram-positive bacteria.
검증된 단계별 안내1
Recall the structural differences between gram-positive and gram-negative bacteria, focusing on their cell wall and outer membrane composition.
Understand that gram-negative bacteria have an outer membrane external to a thin peptidoglycan layer, while gram-positive bacteria have a thick peptidoglycan layer but no outer membrane.
Recognize that the gram-negative outer membrane contains lipopolysaccharides (LPS), which play a key role in the bacteria's antigenic properties and immune system interactions.
Know that the outer membrane of gram-negative bacteria contains porin proteins, which allow selective permeability, so the statement about lacking porins and being impermeable is incorrect.
Conclude that the accurate description is that the gram-negative outer membrane contains lipopolysaccharides contributing to the cell's antigenic properties.
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