Download Chapter 5: Viruses and Monerans

Chapter 5: Viruses and Monerans
Section 5-1 Answer Key
Vocabulary: virus, parasite, host, bacteriophage
Section Review Questions: pg. 135
1. How does a virus reproduce? How does this relate to how the virus causes disease?
The virus injects hereditary material (nucleic acids) into a host cell, causing the host cell to
ignore its normal functions and to produce more virus particles instead. The virus particles then
leave the host cell to infect other cells.
2. Would you classify viruses as living or nonliving? Explain.
Arguments can be made for both sides. Because viruses are not cells, they cannot perform all
the functions of living cells. For example, they cannot take in food or get rid of wastes. This is
support to classify them as nonliving. However, viruses can reproduce. It is the only live
function they can perform, but they need the help of living cells in order to reproduce. Viruses
also have hereditary material. Both reasons to classify it as living.
3. What is a bacteriophage?
A bacteriophage is a virus that infects bacteria.
4. Describe the structure of a virus.
A typical virus consists of a core of hereditary material surrounded by a protein coat. The
protein coat may be any one of or a combination of several different shapes. A typical
bacteriophage virus has a tail and tail fibers, which it uses to attach to a bacterium.
5. Why were scientists unable to study the structure of viruses until after the electron
microscope was invented?
Viruses are too small to be seen with a light microscope.