Under the Microscope

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Under the Microscope
Interest Grabber
Section 19-1

• 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.

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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.

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Section Outline
Section 19-1

• 191 Bacteria
• A. Classifying prokaryotes
• 1. Eubacteria-cell walls contain peptidoglycan (a
  carbohydrate)
• 2. Archaebacteria
• B. Identifying prokaryotes
• 1. Shapes
• 2. Cell walls
• 3. Movement
• C. Metabolic diversity
• 1. Heterotrophs
• 2. Autotrophs
• 3. Releasing energy

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• 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

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Concept Map
Section 19-1
Bacteria
are classified into the kingdoms of
live in harsh environments such as
include a variety of lifestyles such as
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The Structure of a Eubacterium
Section 19-1
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What Viruses Mean to You
Interest Grabber
Section 19-2

• 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?
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Section Outline
Section 19-2

• 192 Viruses
• A. What Is a Virus?
• B. Viral Infection
• 1. Lytic Infection
• 2. Lysogenic Infection
• C. Retroviruses
• D. Viruses and Living Cells

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Figure 19-9 Virus Structures
Section 19-2
Tobacco Mosaic Virus
T4 Bacteriophage
Influenza Virus
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Figure 19-10 Lytic and Lysogenic Infections
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Figure 19-11 Viruses and Cells
Section 19-2
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Bacteria vs. Humans
Interest Grabber
Section 19-3

• Bacteria are all around youin 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.

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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?

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Section Outline
Section 19-3
193 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
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Common Diseases Caused by Bacteria
Section 19-3
Disease
Pathogen
Prevention
Regular dental hygiene Protection from tick
bites Current tetanus vaccination Vaccination Prop
er food-handling practices Maintaining good
health Clean water supplies
Tooth decay Lyme disease Tetanus Tuberculosis Salm
onella food poisoning Pneumonia Cholera
Streptococcus mutans Borrelia burgdorferi Clostrid
ium tetani Mycobacterium tuberculosis Salmonella
enteritidis Streptococcus pneumoniae Vibrio
cholerae
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Common Diseases Caused by Viruses
Section 19-3
Type of Virus
Nucleic Acid
Disease
Cancer Cancer, AIDS Respiratory
infections Chickenpox Smallpox
Oncogenic viruses Retrovirus Adenoviruses Herpesvi
ruses Poxviruses
DNA RNA DNA DNA DNA
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Video
Video
Lytic and Lysogenic Cycles

• Click the image to play the video segment.

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Internet
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 www.SciLinks.org and
  enter the Web Code as follows cbn-6191.
• For links on the lytic cycle, go to
  www.SciLinks.org and enter Web Code as follows
  cbn-6192.

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Section 1 Answers
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.

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Section 2 Answers
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?
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Section 3 Answers
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.

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