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1)
Attachment: the virus meets and then binds to a cell surface receptor, this explains
why viruses often only infect certain species or tissues eg liver compared to neurones 2) Penetration and uncoating: the virus is enveloped by an endosome and is degraded and its nucleic acid escapes into the cytoplasm, no infectious virus remains 3) Formation of
messenger RNA: Viruses have their own polymerase proteins which force the cell to make
a DNA viruses make mRNA in the cell nucleus. RNA virus make mRNA in the cytoplasm. Retroviridae are the exception. They transcribe double-stranded DNA which is then ligated by a viral integrase into the host cell chromosome as a chain of viral genes. |