1. Interest Grabber Under the Microscope
Section 19-1
Under the Microscope
Microorganisms are living things that can only be seen through a microscope. Imagine that you have just discovered a new microorganism. The first thing that you want to do is to tell the scientific community all about your new discovery.

2. Interest Grabber continued
Section 19-1
1. Describe your microorganism in detail.
2. Describe its habitat.
3. Classify your microorganism by giving it a genus and species based on its characteristics.

3. Section Outline 19–1 Bacteria A. Classifying Prokaryotes 1. Eubacteria
2. Archaebacteria
B. Identifying Prokaryotes
1. Shapes
2. Cell Walls
3. Movement
C. Metabolic Diversity
1. Heterotrophs
2. Autotrophs
3. Releasing Energy
D. Growth and Reproduction
1. Binary Fission
2. Conjugation
3. Spore Formation
E. Importance of Bacteria
1. Decomposers
2. Nitrogen Fixers
3. Human Uses of Bacteria

4. Concept Map Section 19-1 Bacteria are classified into the kingdoms of
Eubacteria
Archaebacteria
include a variety of lifestyles such as
live in harsh environments such as
Infecting large organisms
Thick mud
Living in soil
Animal digestive tracts
Salty lakes
Hot springs

5. The Structure of a Eubacterium
Section 19-1
Peptidoglycan
Cell wall
Cell membrane
Ribosome
Flagellum
DNA
Pili

6. What Viruses Mean to You
Interest Grabber
Section 19-2
What Viruses Mean to You
If you have ever had a cold, you are probably familiar with the word virus. It is a word that makes most people frown.
1. What do you think of when you hear the word virus? Make a list of all the words you can think of that relate to viruses.
2. What are two things that you would like to find out about viruses?

7. Section Outline 19–2 Viruses A. What Is a Virus? B. Viral Infection
1. Lytic Infection
2. Lysogenic Infection
C. Retroviruses
D. Viruses and Living Cells

8. Figure 19-9 Virus Structures
Section 19-2
Tobacco Mosaic
Virus
T4 Bacteriophage
Influenza Virus
RNA
Capsid
proteins
Head
Tail sheath
DNA
Tail fiber
RNA
Capsid
Surface
proteins
Membrane
envelope

9. Figure 19-10 Lytic and Lysogenic Infections

10. Figure 19-11 Viruses and Cells
Section 19-2

11. Interest Grabber Bacteria vs. Humans
Section 19-3
Bacteria vs. Humans
Bacteria are all around you—in the air you breathe, under your feet, on your skin, and even in your body! They may be tiny, but they can still have an impact on your life.
Use what you already know about bacteria to answer these questions.

12. Interest Grabber continued
Section 19-3
1. In what ways are bacteria similar to humans?
2. In what ways are bacteria different from humans?
3. How can bacteria be harmful?

13. Section Outline 19–3 Diseases Caused by Bacteria and Viruses
A. Bacterial Disease in Humans
1. Using Cells for Food
2. Releasing Toxins
3. Preventing Bacterial Disease
B. Bacterial Disease in Animals
C. Controlling Bacteria
1. Sterilization by Heat
2. Disinfectants
3. Food Storage and Processing
D. Viral Disease in Humans
E. Viral Disease in Animals
F. Viral Disease in Plants
G. Viroids and Prions
1. Viroids
2. Prions

14. Common Diseases Caused by Bacteria
Section 19-3
Disease
Pathogen
Prevention
Tooth decay
Lyme disease
Tetanus
Tuberculosis
Salmonella food poisoning
Pneumonia
Cholera
Streptococcus mutans
Borrelia burgdorferi
Clostridium tetani
Mycobacterium tuberculosis
Salmonella enteritidis
Streptococcus pneumoniae
Vibrio cholerae
Regular dental hygiene
Protection from tick bites
Current tetanus vaccination
Vaccination
Proper food-handling practices
Maintaining good health
Clean water supplies

15. Common Diseases Caused by Viruses
Section 19-3
Type of Virus
Nucleic Acid
Disease
Oncogenic viruses
Retrovirus
Adenoviruses
Herpesviruses
Poxviruses
DNA
RNA
Cancer
Cancer, AIDS
Respiratory infections
Chickenpox
Smallpox

16. Click the image to play the video segment.
Lytic and Lysogenic Cycles
Click the image to play the video segment.
Video

17. Go Online The latest discoveries in microorganisms and viruses
Links from the authors on smallpox vaccinations
Career links on epidemiologists
Interactive test
Articles on bacteria and viruses
For links on bacteria, go to and enter the Web Code as follows: cbn-6191.
For links on the lytic cycle, go to and enter Web Code as follows: cbn-6192.
Internet

18. Interest Grabber Answers
1. Describe your microorganism in detail.
Students should describe the appearance of their imaginary organism. A possible answer might include its color and shape.
2. Describe its habitat.
Students should describe whether it lives in water, soil, or another organism; if it is a plant or animal; and how it gets its energy.
3. Classify your microorganism by giving it a genus and species based on its characteristics.
Students should specify a name for their organism.
Section 1 Answers

19. Interest Grabber Answers
1. What do you think of when you hear the word virus? Make a list of all the words you can think of that relate to viruses.
Possible answers: disease, sickness, AIDS virus, infection, microscopic, vaccines, flu, cold
2. What are two things that you would like to find out about viruses?
Possible answers: How are viruses related to bacteria? How do viruses cause disease? How do viruses reproduce? How do viruses spread from person to person?
Section 2 Answers

20. Interest Grabber Answers
1. In what ways are bacteria similar to humans?
Like humans, bacteria are alive, and some can move. Both obtain energy, exchange gases, grow, and reproduce.
2. In what ways are bacteria different from humans?
Unlike humans, bacteria are extremely small; some can live in harsher environments and without oxygen; some bacteria use sunlight to produce their own food.
3. How can bacteria be harmful?
Bacteria cause diseases, release poisonous chemicals, and compete with humans for food.
Section 3 Answers

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