NURSING ANM AND GNM

NURSING EXAM QUESTIONS

MICROBIOLOGY

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
Lipid A is a(n) ____ released by ____ bacteria.
A
endotoxin; gram negative
B
endotoxin; gram positive
C
protein; acid-fast
D
hormone; gram positive
Explanation: 

Detailed explanation-1: -Lipid A is a lipid component of an endotoxin held responsible for the toxicity of gram-negative bacteria. It is the innermost of the three regions of the lipopolysaccharide (LPS), also called endotoxin molecule, and its hydrophobic nature allows it to anchor the LPS to the outer membrane.

Detailed explanation-2: -The lipid A component is known to be the endotoxic and pyrogenic centre of the entire lipopolysaccharide molecule, and it is responsible for most of the toxic effects of infections with Gram-negative bacteria.

Detailed explanation-3: -Lipid A is the lipid anchor of a lipopolysaccharide in the outer leaflet of the outer membrane of Gram-negative bacteria. In general, lipid A consists of two phosphorylated N-acetyl glucosamine and several acyl chains that are directly linked to the two sugars.

Detailed explanation-4: -Endotoxin is a major component of the outer membrane of gram-negative bacteria, with lipid A in the membrane and the O-antigen constituting the outer-facing surface of the bacterium. Soluble endotoxin is released when bacteria are destroyed, but is also released physiologically as outer membrane vesicles.

Detailed explanation-5: -When Gram-negative bacteria are killed by the immune system, fragments of their membrane containing endotoxins are released in the blood stream and may cause fever and diarrhoea. The presence of endotoxins in the blood (endotoxemia) typically leads to hypotension, respiratory failure and reduced oxygen delivery.

There is 1 question to complete.