Read Each Question, and Write Your Answer in the Space Provided

Viruses Name: Read each question, and write your answer in the space provided. 1. What is a virus?

2. What properties of life does a virus lack?

3. How do viruses reproduce?

4. List the 4 main shapes of viral structures.

5. What is the function of the tail and tail fibers in a phage?

Match the letter of the description that best defines the term or phrase. 6. Capsid a. a protein with an attached carbohydrate molecule 7. Envelope b. the protein coat of a virus 8. Glycoprotein c. a virus that infects bacteria 9. Bacteriophage d. a membrane that surrounds the capsid of some viruses Define the terms: 10. lytic cycle

11. lysogenic cycle

12. provirus

13. temperate virus

14. HIV

15. AIDS

16. Prion

17. viroid

Read the passage below. Then answer the questions that follow. Viruses lack the enzymes necessary for metabolism and have no structures for making proteins. Therefore, viruses must rely on living cells for reproduction. Before a virus can reproduce, it must first infect a living cell. In bacteriophages— bacterial viruses—the cycle of viral infection, reproduction, and cell destruction is called the lytic cycle. After the viral genetic material has entered the cell, it uses the host cell to replicate viral genes and to make viral proteins, such as capsids. The proteins are then assembled with the replicated viral genes to form complete viruses. The host cell breaks open and releases newly made viruses. During an infection, some viruses stay inside the cells but do not make new viruses. Instead of producing virus particles, the viral genetic material is inserted into the host chromosome and is called a provirus. Whenever the cell divides, the provirus also divides, resulting in two infected host cells. In this cycle, called the lysogenic cycle, the viral genome replicates without destroying the host cell. READING EFFECTIVELY: Read each question, and write your answer in the space provided. 18. Why must viruses rely on living cells for reproduction? How does this make them non-living?

19. What is the main idea of the second paragraph?

SKILL: INTERPRETING GRAPHICS The figure below shows the lytic and lysogenic cycles. Circle and trace each. In the spaces provided, describe what is occurring in each numbered part of the figure.

20. Part 1:

21. Part 2:

22. Part 3:

23. Part 4:

24. Part 5:

25. Which stage is the dormant stage of the viral reproduction cycle?

26. If you are showing signs of a viral infection, what stage of a virus’s reproduction is giving the symptoms?

27. Are antibiotics effective against virus? Why or why not?