Virus Notes (Chapter 19 Section 3)
VIRUSES (Read Pages 482 - 487 and fill in the following)
1. What is a virus?
Virus Structures
Viruses come in a variety of sizes and shapes. A typical virus is composed of a core and either DNA
or RNA, surrounded by a protein coat, or capsid. Label the following parts on the viruses found
below: Head, Tail Sheath, DNA, Tail Fiber, RNA, Capsid, Surface Proteins & Membrane Envelope.
Viral Infection
Viruses must bind precisely to _______________________ on the cell surface and then use the
host’s __________________ system. Most viruses are highly specific to the cells they infect.
The following are the two different ways in which a virus can cause infection:
Lytic Cycle
Lysogenic Cycle
1. Briefly explain what happens during the lytic cycle.
2. Explain how the lysogenic cycle differs from the lytic cycle.
3. What is a prophage, and during which type of viral replication is it formed?
4. What is a host?
5. Explain how the lytic and lysogenic cycles are linked.
Viruses and Disease
Briefly explain the following based off what you read on pages 486 and 487 of your textbook.
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Viruses and Cancer -
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Retroviruses -
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Prions -