8. What is peptidoglycan? 9. Some eubacteria have a second, outer
.
10. Circle the letter of each sentence that is true about archaebacteria. a. Their membrane lipids are different from those of eubacteria. b. They lack a cell wall. c. They lack peptidoglycan. d. They look very similar to eubacteria. 11. What is significant about the DNA sequences of key archaebacterial genes? 12. How are archaebacteria related to eukaryotes?
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Chapter 19, Bacteria and Viruses (continued) 13. What are methanogens, and where do they live?
14. Complete the illustration of a typical prokaryote by labeling the parts.
Identifying Prokaryotes
(page 473)
15. What are four characteristics used to identify prokaryotes? a. b. c. 16. What are each of the differently shaped prokaryotes called? a. The rod-shaped are called
.
b. The spherical-shaped are called
.
c. The corkscrew-shaped are called
.
17. A method of telling two different types of eubacteria apart by using dyes is called
.
18. What colors are Gram-positive and Gram-negative bacteria under the microscope when treated with Gram stain? 19. What are flagella? 20. Is the following sentence true or false? Many prokaryotes do not move at all. 158
21. Complete the table about prokaryotes classified by the way they obtain energy. GROUPS OF PROKARYOTES Group
Description Organism that carries out photosynthesis in a manner similar to plants
Chemoautotroph
Organism that takes in organic molecules and then breaks them down Photoheterotroph
22. Members of which group of photoautotrophs contain a bluish pigment and chlorophyll a? 23. How do the chemoautotrophs that live near hydrothermal vents on the ocean floor obtain energy?
Releasing Energy
(page 475)
24. Complete the table about prokaryotes classified by the way they carry out respiration. GROUPS OF PROKARYOTES Group
Organisms that require a constant supply of oxygen Obligate anaerobes Facultative anaerobes
25. How is botulism caused? 26. Facultative anaerobes can switch between cellular respiration and .
Growth and Reproduction
(page 476)
27. What occurs in the process of binary fission?
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Chapter 19, Bacteria and Viruses (continued) 28. What occurs during conjugation? 29. Is the following sentence true or false? Most prokaryotes reproduce by conjugation. 30. What is an endospore?
Section 19–2 Bacteria in Nature
(pages 477–481)
This section describes ecological roles bacteria play in the environment. It also explains how bacteria cause disease.
Decomposers
(page 477)
1. How do decomposers help the ecosystem recycle nutrients when a tree dies?
2. What would happen to plants and animals if decomposers did not recycle nutrients?
Nitrogen Fixers
(page 478)
3. Why do plants and animals need nitrogen?
4. How does nitrogen fixation help plants?
fixing bacteria?
Bacteria and Disease
(pages 479–480)
6. What are pathogens? 7. What are the two general ways that bacteria cause disease? a. b. 8. What kind of tissue do the bacteria that cause tuberculosis break down? 160
5. What kind of relationship do many plants have with nitrogen-
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9. What are most cases of food poisoning caused by? 10. What are antibiotics? 11. What is one of the major reasons for the dramatic increase in life expectancy during the past two centuries?
Human Uses of Bacteria
(page 480)
12. In the production of what foods are bacteria used? 13. How can bacteria be used to clean up an oil spill? 14. What have biotechnology companies begun to realize about bacteria adapted to extreme environments?
Controlling Bacteria
(page 481)
15. What is sterilization? 16. A chemical solution that kills bacteria is called a(an) .
17. Why will food stored at low temperatures keep longer? 18. How can food be preserved through canning?
19. What everyday chemicals can be used to inhibit the growth of bacteria in food?
Reading Skill Practice Writing a summary can help you remember the information you have read. When you write a summary, write only the most important points. Write a summary of the information under the blue heading Decomposers. Your summary should be shorter than the text on which it is based. Do your work on a separate sheet of paper.
Guided Reading and Study Workbook/Chapter 19
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Chapter 19, Bacteria and Viruses (continued)
Section 19–3 Viruses
(pages 482–487)
This section describes the structure of a virus. It also explains how viruses cause infection.
What Is a Virus?
(pages 482–483)
1. What are viruses? 2. What do all viruses have in common?
3. Is the following sentence true or false? Most viruses are so small that they can be seen only with the aid of a powerful electron microscope. 4. What is the structure of a typical virus? 5. Circle the letter of what a virus’s protein coat is called. a. capsid
b. envelope
c. head
d. lysis
6. How does a typical virus get inside a cell?
7. What occurs when viruses get inside of cells?
(pages 484–486)
8. Why are most viruses highly specific to the cells they infect?
9. What are bacteriophages? 10. Why is the process called a lytic infection? 11. Circle the letter of each sentence that is true about a lysogenic infection. a. The virus lyses the host cell immediately. b. The virus embeds its DNA into the host’s DNA. c. The virus’s DNA is replicated along with the host cell’s DNA. d. A host cell makes copies of the virus indefinitely. 162
16. How does a vaccine prevent a viral disease when injected into the body? 17. Cancer-causing viruses are known as . 18. What are retroviruses? 19. What happens when retroviruses infect a cell?
20. A disease-causing particle that contains only protein and not DNA or RNA is called a(an)
Guided Reading and Study Workbook/Chapter 19
.
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Chapter 19, Bacteria and Viruses (continued)
Are Viruses Alive?
(page 487)
21. Circle the letter of each reason why biologists do not consider viruses to be alive. a. They can’t infect living cells. b. They can’t evolve. c. They can’t regulate gene expression. d. They can’t reproduce independently.
WordWise Answer the questions by writing the correct vocabulary terms in the blanks. Use the circled letter in each word to find the hidden word. Then, write a definition for the hidden word. What is the viral DNA that is embedded in a host’s DNA? What is a rod-shaped bacterium? What is a compound that blocks the growth and reproduction of bacteria? What is a virus that infects bacteria? What is a prokaryote that can capture sunlight for energy but also needs organic compounds for nutrition?
What is a virus that contains RNA as its genetic information? What is the process in which nitrogen is converted into a form plants can use?
