1. Label the Picture Below. Read the Section What Is a Virus? on Page 478 to Do This

Name: ______Hr: ___ Viruses (19-2)

1. Label the picture below. Read the section “What is a Virus?” on page 478 to do this.

Head DNA Capsid

Tail Fibers Surface Proteins Membrane envelope

2. What is a virus made of? Core of DNA or RNA and a protein coat called a “capsid”; surface proteins

3. What does the word virus mean? “poison”

4. Viruses that infect bacteria are called __bacteriophages______.

5. Study the incorrect statements below. Change the underlined word(s) to make each sentence correct. Write the correct new word(s) on the line. a. Viruses are in the kingdom Archeabateria. _not alive or not in a kingdom_

b. Viruses are made of cells. _DNA/RNA and Capsid_

c. Viruses can be seen with a light microscope. _an electron_

d. Viruses can cause damage only in humans. _all kinds of organisms_

e. Each kind of virus infects several hosts. _certain types of hosts_

f. Viruses are always larger than the cells

they infect. __smaller___

g. Viruses reproduce outside of living cells. __inside______

h. Viruses do not harm the cells in which they live. __kill_____ 6. Using the section on lytic infection on page 480, put the following pictures in the correct order. Also, describe what is happening at each stage.

Order 4 1 5 2 3

1 virus attaches 2 virus 3 virus parts 4 virus 5 cell gets so What is itself to a injects its are made parts are full of viruses happening? specific cell DNA/RNA assembled it errupts

7. What is the difference between a lytic and lysogenic infection? Lytic: virus enters cell, makes copies of itself, and causes cell to burst Lysogenic: virus intergrates its DNA into the DNA of host cell, and viral genetic info replicates along with the host cell’s DNA. Lysogenic infection can stay inactive for a period of time and then enter the lytic stage (causing cell to burst)

8. Viruses are sometimes confusing to scientist because they show signs of acting both alive and not alive. List three things they have in common with living things (cells). a. Have a genetic code (DNA or RNA)

b. Change over time

c. Reproduce (but require a host cell)

9. List three reasons why scientists do not believe viruses are alive. a. no growth and development

b. don’t obtain and use energy

b. Don’t respond to environment

10. Read the section on Preventing Bacterial Disease, page 486.

Some bacterial and viral diseases can be prevented using a __vaccine______.

What type of infection are antibiotics used for? _bacterial only, viruses will not respond to antibiotics______