The outer membrane of gram-negative bacteria contains lipopolysaccharide, with lipid A functioning as an endotoxin that can cause fever and shock.

The outer membrane of gram-negative bacteria contains lipopolysaccharide (LPS), a complex molecule with three components: lipid A, a core polysaccharide, and an O-antigen. Lipid A is embedded in the outer membrane and acts as an endotoxin. When released during bacterial lysis or multiplication, lipid A triggers a strong immune response, leading to fever, inflammation, and in severe cases, septic shock. This property makes gram-negative infections potentially life-threatening. The presence of LPS also contributes to the structural integrity of the outer membrane and provides resistance to certain antibiotics.

The COVID-19 virus, scientifically known as SARS-CoV-2, is an RNA virus, not a DNA virus. Its genetic material consists of single-stranded positive-sense RNA, which serves as a template for viral replication and protein synthesis inside host cells. RNA viruses generally have higher mutation rates than DNA viruses due to the lack of proofreading mechanisms during replication. Understanding the RNA-based genome of SARS-CoV-2 is crucial for developing diagnostic tests, vaccines, and antiviral therapies. Classifying it correctly as an RNA virus also distinguishes it from DNA viruses, which replicate using DNA as their genetic material and follow different replication strategies.