Viruses — Flashcards

Flashcard 561: Orthomyxovirus has _____ segments

Answer: 8 (#)

Flashcard 562: Which viral virulence factor causes respiratory cell fusion and multinucleated giant cell production?_____

Answer: F (fusion) protein

Flashcard 563: Which virus causes hemorrhagic fever with renal syndrome (HFRS)?_____

Answer: Hantaan virus (and other Old World hantaviruses)

Extra: Hantaviruses cause two distinct clinical syndromes: 1. **Hemorrhagic Fever with Renal Syndrome (HFRS)**: Caused by Old World hantaviruses (e.g., **Hantaan virus**, Seoul, Puumala). 2. **Hantavirus Pulmonary Syndrome (HPS)**: Caused by New World hantaviruses (e.g., **Sin Nombre virus**, Andes virus).

Flashcard 564: The _____ cycle is when a phage injects genetic material into a bacterium, multiplies, and then lyses the cell, releasing the new viruses.

Answer: Lytic (Lytic vs. Lysogenic)

Flashcard 565: Which virus family causes molluscum contagiosum?

Answer: Poxvirus

Flashcard 566: Picornaviruses produce a large _____ (inactive) that is cleaved into smaller subunits (active)

Answer: polyprotein product

Flashcard 567: A definitive diagnosis of infectious mononucleosis is made by serologic testing for the EBV _____ antigen

Answer: viral capsid

Flashcard 568: How many different MHC class I molecules are typically expressed on a single nucleated cell?

Answer: 6 (2 alleles each for HLA-A, HLA-B, and HLA-C)

Flashcard 569: Which viral genetic phenomenon is characterized by the acquisition of a new viral surface protein (e.g., Hemagglutinin) from another virus during co-infection?

Answer: Phenotypic mixing

Flashcard 570: Where does class switching of IgM take place?_____

Answer: Germinal centers of lymph nodes