Slide 1 shows a bacteriophage - a virus that attacks only bacterial cells. The
virus is actually a rather complicated structure, consisting of a head, collar,
tail, and tail fibers.
T-bacteriophages on E. coli. Colored TEM of T-Baccteriophage viruses attacking
a bacterial cell of Escherichia coli. Seven virus particles are seen (blue),
each with a head and a tail. Four of these are "sitting" on the
brown bacterial cell and small blue "tails" of genetic material
(DNA) are injected into the bacterium. T-bacteriophages are parasites of
bacterial cells. The virus attaches itself to the cell's wall and, using
it's tail as a syringe, injects it's own DNA into the bacterium. The virus
DNA then takes over the bacterial cell, forcing it to produce more viruses.
Credit: Eye of Science / Photo Researchers, Inc.
