Biology, Eighth Edition (Raven)

Chapter 14: DNA: The Genetic Material

Steps in the Replication of T4 Phage in E. Coli

Why are viruses virulent? Viruses require cells to replicate themselves. They are parasites. They are also pathogens, entities that cause disease. Pathogens vary in their virulence, the extent to which they are harmful to their hosts. Pathogens may evolve reduced virulence if their probability of transfer to a new host at any given point in time is low. If a virulent virus had a low probability of reaching a new host, individual viruses that did not seriously harm their host would tend to persist. Highly infectious viruses such as those causing influenza will not tend to evolve reduced virulence.

View the animation below, then complete the quiz to test your knowledge of the concept.



1.

The stage of T4 replication that involves the protein fibers on the phage and receptors on the bacterial cell wall is the...
A)assembly stage.
B)attachment stage.
C)lysis stage.
D)transcription stage.
E)penetration stage.
2.

The stage of T4 replication that involves the injection of phage DNA is the...
A)assembly stage.
B)attachment stage.
C)lysis stage.
D)transcription stage.
E)penetration stage.
3.

The stage of T4 replication that involves the copying of the phage DNA and the synthesis of various phage proteins is the...
A)assembly stage.
B)attachment stage.
C)lysis stage.
D)transcription stage.
E)penetration stage.
4.

The enzyme lysozyme is used by the T4 phages to enter and exit the host cell.
A)True
B)False
5.

During the transcription stage, the phage DNA merges with the host DNA.
A)True
B)False
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