Case study #2: influenza an example of an orthomyxovirus. Highly contagious, acute respiratory illness influenza. Host imposes 5 limitations on viral replication: host doesn"t have enzyme that can read and synthesize rna. Virus encodes its own rdrp: viral genome is (-) rna, host ribosome can"t translate (-) rna. Virus steals 5" cap from host mrnas: host ribosomes translate only monocistronic mrnas. Virus uses host rna splicing enzymes to ensure all genes translated: describe the structure of influenza virus: its genome (negative ssrna), the rnp structures, its envelope, and the proteins within the envelope. Genome: 8 segments of single-stranded (-) rna (7 in flu c): 6 of segments code for 1 protein, 2 segments code for 2 proteins each. Spliced to allow for translation of second gene: 10 genes coded in total, segments of genome called ribonucleoproteins (rnps) and consists of rna and nucleoprotein (np). Each rnp has 4 diff proteins and rna.