Virus Notes (Chapter 19 Section 3) VIRUSES Virus Structures

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.
Viruses and Cancer -
Retroviruses -
Prions -