Exam 9: Viruses and Virology

The packaging mechanism of T4 DNA involves cutting of DNA from

T4 bacteriophage contains 5- hydroxymethylcytosine that replaces_________ and is a protectant against __________.

Rod- shaped viruses have_________ symmetry, and spherical viruses have _ symmetry.

Lambda and other temperate viruses have an exceedingly complex genetic switch that_________.

In the first few minutes after host cell infection, the virus undergoes an eclipse.

The term "phage" is generally reserved for the viruses that infect_________ .

The two events necessary to establish lysogeny for lambda phage are _________and_________.

Explain why some viruses contain enzymes within the virion and others do not.

In viruses, genetic information flows from _________to_________ .

Lambda is

The use of_________ has greatly enhanced research on most animal and many plant viruses.

Viruses have both an intracellular and an extracellular form.

Although T4 encodes over 250 proteins, it does not encode its own RNA polymerase.

Some viruses possess icosahedral heads and helical tails.

A lytic infection results in death of the host cell.

Reverse transcriptase is a(n)

Viruses can confer additional properties on their host cells, which can in turn be inherited.

Patrick Forterre's hypothesis states that an RNA virus infected a cell to form the last universal common ancestor (LUCA).

Describe the structure of the T4 virus, and explain this virus's attachment and penetration processes in terms of this structure.

Enveloped viral membranes are generally_________with associated virus- specific_________.