Viruses

• Viruses can have both single and double stranded RNA and DNA as their genetic information
• Negative sense RNA viruses have a lipid envelope and need to replicate their RNA strand to make coding MRNA
• Positive sense RNA viruses sometimes have a lipid envelope and have mRNA so can instantly perform protein synthesis in the host
• DNA viruses can be circular by covalent bonding and have a large genome size
• Viruses can have overlapping genes or be read backwards to encode more proteins
• Double stranded RNA viruses have no lipid envelope
• Viruses have strong promotor regions to ensure their proteins are highly expressed
• Viruses steal envelopes from organelles and the lipid membrane
• Viruses affinity to a host is affected by amount of virus ligand, receptors, and amount of specific host cells available
• Budding viruses can damage the cell membrane, but tend to lead to long, chronic infection
• Lysing viruses cause cell death and rapid infection
• RNA viruses have a high mutation rate due to no DNA polymerase exonuclease
• Double stranded DNA viruses integrate their DNA into the host cell directly
• Viruses mature outside of the host cell to prevent infection of the same host cell
• Positive sense RNA viruses begin mRNA translation immediately
• Retroviruses use reverse transcriptase to integrate their RNA as DNA into the host using integrase enzyme