Question

1. The RNA virus's ability to produce tumors is related to the presence of_________?

2. ___________ cause release of cytokins, which cause fever, nausea, and other symptoms; e.g., toxic shock syndrom toxin.

3. Invasive__________ streptococci cause severe and rapid tissue destruction.

Answer 1

1. Reverse transcriptase

RNA has enzyme reverse transcriptase which helps to penetrate into the host cell and replicate to produce tumour .Reverse transcriptase is a RNA directed DNA polymerase which catalyse the transcription of viral RNA (Ribonucleic acid) into DNA ( Deoxyribonucleic acid). This viral DNA combine with the host DNA and turn them into cancer cells.

Example: Retroviruses.

2.Superantigens

Super antigens are antigens that cause excessive activation of immune system.They(exotoxins) are produced by some pathogenic bacteria like staphylococcus aureus and group A streptococcus .It causes polyclonal T cell activation and massive release of cytokines.when these cytokines are released into blood it causes fever,nausea or toxic shock syndrome .

3.Group A

Invasive group A streptococcus cause rapid and severe tissue destruction.The infection caused by this bacteria reach different parts of the body and cause invasive diseases like necrotising fascitis and streptococcal toxic shock syndrome. Necrotising fascitis is the infection that destructs muscle and fat tissues ,hence it is also known as flesh eating bacteria.