BSC 444 Lecture Notes - Lecture 6: Cytoskeleton, Lipid Bilayer, Provirus
16 Sep 2017
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Document Summary
Naked viruses attach via: ridges or depressions on the capsid surface, specialized structures (knobs, fibers, spikes) Ionic attractions: van der waals forces, no covalent bonds. Initially weak: virion bound to only one or a few receptors, attachment is initially reversible, later strong, more attachment sites of the virion bind to additional receptors, attachment becomes irreversible. Animal virus entry: two routes to cross the plasma membrane, cross at the cell surface, cross the membrane of an endosome (endocytosis) Entry of naked viruses (usually via endocytosis): stages, reversible attachment, irreversible attachment, endocytosis, release from endosome. Entry of enveloped viruses: two common mechanisms, endocytosis, cell surface fusion, both require fusion of the envelope with a cell membrane. Insertion into target membrane: bring 2 membranes together, two trigger types, ph independent (cell surface, acid-triggered (endosome) Nuclear envelope: structure enclosing the nucleus, composed of two membranes each is a lipid bilayer, contains ~3000 to 5000 nuclear pores.
