Chapter 16.3.1 (Exam 4) Viruses

Question 1

How do viruses reproduce?

Answer 1

Viral genomes have sequences that encode regulatory proteins that “hijack” the host cells’ transcriptional machinery

Question 2

What are the two vial reproductive cycles?

Answer 2

Lytic cycle

Lysogenic cycle

Question 3

What is the lytic cycle?

Answer 3

Soon after infection, the host cell lyses, releasing progeny viruses

Question 4

What is the lysogenic cycle?

Answer 4

Viral DNA integrates with the host DNA and is not expressed

The inserted bacteriophage genome is called a prophage

Question 5

What is a prophage?

Answer 5

The inserted bacteriophage genome in the lysogenic cycle that integrates with the host DNA but is not expressed

Question 6

If the viral DNA is not expressed during the lysogenic cycle, how does it aid in viral reproduction?

Answer 6

Host cells with the silently integrated viral DNA reproduce

Eventually the virus switches to the lytic cycle, and many viruses are produced as viral DNA is expressed

Question 7

When does the virus switch from the lysogenic to the lytic cycle?

Answer 7

A virus switches from the lysogenic to the lytic cycle when the host cell is under stress or damaged, triggering the virus to start reproducing immediately