Questions: Which of the following does not pertain to endotoxin? It is found in acid-fast bacterial cell walls

The answer is the second one: It is found in acid-fast bacterial cell walls.

Explanation for each option:

1. It can stimulate fever in the human body: This is correct. Endotoxins, which are part of the outer membrane of Gram-negative bacteria, can stimulate the immune system and cause fever.

2. It is found in acid-fast bacterial cell walls: This is incorrect. Endotoxins are not found in acid-fast bacterial cell walls. Acid-fast bacteria, like Mycobacterium, have a unique cell wall structure rich in mycolic acids, not endotoxins. Endotoxins are specifically associated with the lipopolysaccharide (LPS) layer of Gram-negative bacteria.

3. It can cause septic shock in the human body: This is correct. Endotoxins can trigger a strong immune response, leading to septic shock, a severe and life-threatening condition.

4. It is a specific cell wall lipid: This is correct. Endotoxins are part of the lipopolysaccharide (LPS) complex in the outer membrane of Gram-negative bacteria, which includes lipid A, a specific lipid component.

5. It is involved in typhoid fever and some meningitis cases: This is correct. Endotoxins are associated with Gram-negative bacteria, such as Salmonella typhi (causing typhoid fever) and Neisseria meningitidis (causing meningitis), which can release endotoxins during infection.

In summary, endotoxins are not found in acid-fast bacterial cell walls, making the second option the correct choice for what does not pertain to endotoxin.