2 - Viral Replication

Eclipse

What is the term for the period after the virus penetrates the cell and until the first progeny become visible? It is constant depending on the virus family between 2-12 hours and is important for giving antiviral drugs.

Susceptible

What type of cell line is those which can be infected by a virus but do not allow replication to be completed?

Permissible

Which type of cell lines are those which allow replication of viruses to be completed?

Infectious Clones

What are constructed if viruses are unculturable, and are done by injecting viral genomes into cells to be replicated?

Receptors, Coreceptors

In the attachment stage of viral replication the virus will attach to complementary what two things on the host cell surface with their capsids? These will only be present on susceptible cells.

Membrane Fusion

What type of viral penetration is used by enveloped viruses and involves blending of the envelope with the cell membrane?

Endocytosis

What type of viral penetration is done by naked viruses and is receptor mediated?

Genetic Injection

What type of viral penetration process is done by some viruses by putting only the viral genome into the cell?

Chaperones

What types of cellular proteins are used by the nonmotile virus in the uncoating stage of replication to take the genome to the nucleus if that is necessary for replication?

5-3

What direction is transcription done if it is positively poled?

3-5

What direction is transcription done if it is negatively poled?

Positive

RNA viruses poled how will use ribosomes to replicate?

Negative

RNA viruses poled how will not use ribosomes and instead will use their own polymerases to replicate in the host cell?

Retrotranscriptase

RNA dependent DNA polymerases are used by retroviruses and are also called what?

RNA dependent RNA polymerase

What viral enzyme is used by RNA viruses to replicate?

DNA dependent RNA polymerase

Which viral enzyme is used by DNA viruses which replicate in the cytoplasm? It is used by mRNA synthesis.

Cap

In post translational processing of viruses what is usually added to facilitate formation of a stable complex with the 40S ribosomal unit necessary for translational initiation?

Poly A tail

What section of the genome is a recognition signal for transport from the nucleus to the cytoplasm and protects the mRNA against degradation?

Polycistronic

Are viral mRNAs poly or monocistronic? Cellular mRNAs are monocistronic.

Helical

Viruses with what type of structure will self-assemble in a similar appearance to a pearl necklace?

Packing

What type of sequence will be found on one end of the viral genome which will bind to a protein, enabling the virus to enter the procapsid?

Lysis

What process of release is used by naked viruses, when they accumulate in the nucleus or cytoplasm?

Budding, Exocytosis

What are the two possible methods of release for enveloped viruses from the host cell?

Double

The DNA intermediate used by retroviruses is double or single stranded?

Long Terminal Repeats

What is the term for the additional sequences on each end of the double-stranded DNA intermediate used by retroviruses? They are important for allowing the viral genome to integrate to the host genome and for acting as a strong promotor. The DNA itself will be called the proviral DNA and is used for transcription of viral RNA.