The genetics of viruses：练习题

Which structure surrounds the nucleic acid core of all viruses?

What is the primary role of the viral enzyme integrase during the reproductive cycle of HIV?

Why does the genetic material of an RNA virus like influenza mutate at a substantially higher rate than that of a double-stranded DNA virus during replication?

What is the term used to describe a bacteriophage genome that has integrated into the circular bacterial chromosome during the lysogenic cycle?

During the lysogenic cycle of bacteriophage lambda (λ), which event ensures the maintenance of the prophage state in the host Escherichia coli bacterium?

State the structural component of an enveloped virus, such as the influenza virus, that is derived directly from the host cell's membrane system during viral egress.

Distinguish between antigenic drift and antigenic shift in influenza viruses in terms of the underlying genetic mechanism involved in each.

Explain why the replication of the influenza virus genome exhibits a significantly higher mutation rate compared to the replication of double-stranded DNA bacteriophages.

Influenza virus is an enveloped RNA virus that causes seasonal epidemics.
(a) State the functions of the two major surface glycoproteins found on the lipid envelope of the influenza virus.
(b) Outline the mechanism of viral entry into the host cell and the release of progeny virions from the host cell.

The influenza virus exhibits two mechanisms of genetic variation: antigenic drift and antigenic shift.
(a) Explain the molecular basis of antigenic drift and explain why it necessitates annual updates to seasonal flu vaccines.
(b) Describe the mechanism of antigenic shift and explain why it can result in global influenza pandemics.