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Chapter 19
Viruses
Question | Answer |
---|---|
virus | an infectious particle consisting of little more than genes packaged in a protein coat |
capsid | the protein shell enclosing the viral genome is called a capsid. |
viral envelopes | derived from the membranes of the host cell, contain host cell phospholipids and membrane proteins |
viral replicative cycle | -virus enters the cell and is uncoated, releasing viral DNA and capsid proteins -Host enzymes replicate the viral genome -host enzymes transcribe the viral genome into viral mRNA -viral genome exit cell |
relicative cycle of an enveloped RNA virus | -Glycoproteins on the viral envelope bind to receptor -Viral genome release -Sythesized complementary RNA strands - new copies RNA and translation -transport and assemble |
reverse transcriptase | transcribes an RNA template into DNA, an RNA-->DNA information flow that is the opposite of the usual direction. |
provirus | never leaves the host's genome, remaining a permanent resident of the cell |
vaccine | harmless derivative of a pathogen that stimulates the immune system to mount defenses against the harmful pathogen |
antibiotics | help recover from bacterial infection are powerless against viruses. Kill bacteria by inhibiting enzymes specific to bacteria but have no effect on eukaryotic or virally encoded enzymes |