Download Chapter 5: Viruses and Monerans

Chapter 5: Viruses and Monerans
Section 5-2 Answer Key
Vocabulary: decomposers, symbiosis, antibiotics
Section Review Questions: pg. 147
1. Describe two ways in which bacteria are helpful and two ways in which they are harmful.
There are multiple answers that can be correct for this question. Here are just some examples. Bacteria are
helpful in the production of certain antibiotics and in the manufacture of dairy products. Bacteria are harmful
because they can cause infections in the human body and cause food to spoil.
2. What is an endospore? How does it help bacteria survive?
An endospore is a small cell that is resting internally and is surrounded by a thick, protective coat. It helps
monerans (bacteria) survive during periods of unfavorable growth conditions in the environment.
3. Describe the structure of a bacterium.
A bacterium contains cytoplasm, which is surrounded by a cell membrane, which in turn is surrounded by a cell
wall. This cell wall may be covered by a coating called the capsule. The bacterium’s hereditary material is
spread throughout the cytoplasm, and there is no nucleus. Many monerans or bacteria have one or more
flagella.
4. Many antibiotics work by damaging a bacterium’s cell wall. Explain why such antibiotics are not effective
against viruses and certain kinds of bacteria that lack cell walls.
Antibiotics that affect cell walls are not effective against viruses because viruses lack cell walls. Once inside a
host cell, viruses contain only the characteristics of the host cell. To eliminate a virus, its host cells must be
destroyed. Bacteria that lack cell walls are not harmed by substances that affect cell walls.