BIOL 1002 Chapter : BIOLOGY
Document Summary
Section 6. 2 the position of viruses in the biological spectrum. Viruses on the biological spectrum: viruses can infect every type of cell: Rather than organisms: active or inactive. Rather than alive or dead: obligate intracellular parasites: Cannot multiply unless they invade a specific host cell. Must instruct the genetic and metabolic machinery of the host cell to make and release new viruses. Electron microscopes are required to detect them. >mimiviruses: 450nm in length larger than some small bacteria. >cylindrical viruses: 800nm long, but 15nm in diameter. Viral components: capsids, envelopes, and nucleic acids: viruses bear no resemblance to cells lack protein-synthesizing machinery, need only those parts required to invade and control a host cell: Viral components: capsids: shell surrounds the nucleic acid. Nucleocapsid: capsid and nucleic acid together: envelope: Usually a modified piece of the host cell membrane: naked viruses: consist only of a nucleocapsid, spikes: found on both naked and enveloped viruses. Project from either the nucleocapsid or envelope.
