Introduction:
a. What does the term bacteriophage mean?

Slide 1: Lambda Phage on E.coli:
a. Under what magnification was this picture taken?
b. What part of the virus in this slide is anchored to the bacterium? [head or tail]
c. Indicate your estimate of the length of the bacterium. Don’t forget units. (Use the micron scale in the slide)
d. Indicate your estimate of the length of the virus. Don’t forget units.
e. Why does the bacterium look so different here from the way it looks under a light microscope? (color or the bacteria compared to the background)
f. Why does a filter catch bacteria, but allow viruses to pass through?

Slide 2: Disrupted Phage
a. Draw the disrupted phage on your paper.
b. On your drawing, label the DNA mass, head, tail, and filaments.
c. Chemically speaking, a virus consists of a ___________ shell filled with ________ acid.

Slide 3: Human Viruses
a. Which virus, influenza or polio, is magnified more in this picture?
b. The influenza virus mutates readily. What does this mean?
c. After you have the flu, are you immune to other forms of influenza as well?
d. Mrs. Berry’s great uncle died of polio when he was only 14 years old (in the 1950s). Why do we not hear of children having polio these days?
e. Give 4 examples of other diseases caused by viruses.

Slide 4: Measles Virus Attack
a. Draw a normal human cell AND a cluster of cells infected with measles virus.
b. How can you tell that there were originally eight cells in this group?
c. Have the nuclei changed shape? How?
d. Why can’t you see the individual viruses?

Slide 5: Animal Viruses
a. Give 4 examples of animal viruses.
b. Is there a head and tail structure for the Newcastle virus?
c. What does the vaccinia virus cause?
d. Can you see the DNA core inside the vaccinia virus?
e. What is the shape of this virus? (Remember, it has 3 dimensions; the slide only shows 2)
f. Why do you think milkmaids (the girls who milked cows) were often immune to smallpox?
 

Slide 6: Viruses Emerging from Cell
a. Draw what you see in this slide.
b. Label the cell membrane and the viruses that are breaking out of the cell.
c. Do you see any other viruses that are already completely free of the cell?
d. What do you think they will eventually do?

Slide 7: Tobacco Mosaic Virus
a. Draw the virus crystal shown in this slide
b. Why don’t you see all of the tobacco leaf hair cell in this slide? (think about perspective)
c. Does the fact that viruses can form crystals imply that crystals may be alive? Explain.

Slide 8: Cancer Virus
a. Viruses were first found to cause cancer in what animal?
b. What animal is affected by the papilloma virus?
c. Can viruses infect cells if they don’t have tails?