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Interest Grabber
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.
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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
19–1
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Bacteria
A. Four Phyla
1. Eubacteria
2. Archaebacteria
3. Prochlorobacteria
4. Cyanobacteria
5. All bacteria - prokaryotes
B. Identifying Bacteria
1. Cell Shape
a. Rod-shaped – Bacillus (Bacilli)
b. Spherical – Coccus (Cocci)
c. Spiral – Spirillum – (Spirilla)
C.
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2. Cell Walls
a. Gram Stain
b. Purple - Gram +
c. Red – Gram 3. Movement
a. Flagella
b. Lash like snake
c. Glide along layer of slime-like material
Eubacteria vs Archaebacteria
1. Arch. – lack peptidoglycan & have different membrane lipids
2. Arch. – genes resemble genes of eukaryotes
3. Arch. – live in harsh environments
D. Obtaining Energy
1. Autotroph
a. Phototrophic – uses light
b. Chemotrophic
2. Heterotrophs
a. Chemoheterotrophs – must take in organic molecules
b. Phototrophs – use sunlight as energy, but have to take
in organic molecules
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E.
F.
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Bacterial Respiration
1. Obligate aerobes – require constant supply of O2
2. Obligate anaerobes – don’t require O2
Ex: Clostridium botulinum
3. Facultative anaerobes – can survive w/ or w/o O2
Growth and Reproduction
1. Binary fission
a. Asexual reproduction
b. Cell splits into two cells
2. Conjugation
a. Sexual reproduction
b. Exchange of genetic information
3. Spore formation
a. Growth conditions unfavorable
b. Endospore
1. Thick inner wall
2. Encloses DNA & cytoplasm
G. Importance of Bacteria (p 476-477)
1. Decomposers – return nutrients to the the soil and remove solid
waste
2. Nitrogen fixers – convert nitrogen into a form plants can use
3. Human Uses of Bacteria – digest petroleum, remove waste
products from water, mining
minerals
synthesize drugs, make vitamins
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G. Importance & Uses of Bacteria
1. Beverages
2. Cheeses
3. Yogurt
4. Buttermilk
5. Sour cream
6. Digest petroleum
7. Form symbiotic relationships w/other organisms
H. Environment
1. Nutrient Flow
a. Recycle & decompose dead material
b. Saprophytes – break down dead material
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Quick Quiz
1. Define Prokaryote
2. What kingdom do Bacteria belong to?
3. During DNA replication, Adenine always pairs with
________.
4. During DNA transcription, Thymine is replaces with
________.
5. Name three types of RNA.
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2. Sewage Decomposition
a. Human waste
b. Crop fertilizers
3. Nitrogen fixation
a. Rhizobium
b. Cyanobacteria
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Concept Map
Section 19-1
Bacteria
are classified into the kingdoms of
Eubacteria
Archaebacteria
include a variety of
lifestyles such as
Living in soil
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Infecting large
organisms
live in harsh
environments such as
Thick mud
Animal
digestive
tracts
Salty lakes
Hot springs
The Structure of a Eubacterium
Section 19-1
Ribosome
Peptidoglycan
Cell
Cell
wall membrane
Flagellum
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DNA
Pili
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?
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Quick Quiz
1.
The process by which bacteria exchange genetic material is called:
____________________________________________________.
2.
When conditions become unfavorable for growth some bacteria will
form a: _____________________________________________.
3.
When a bacterial cell is classified as an obligate aerobe it means:
4.
When a bacterial cell is classified as a chemoautotroph it means:
5.
Spherical-shaped bacteria are called: _____________________.
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Section Outline
Section 19-2
19–2
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Viruses
A. What Is a Virus?
1. Piece of DNA or RNA
2. Protein Coat (Capsid)
3. Classified as Non-Living
B. Viral Infection
1. Lytic Infection
a. Virus enters cell
b. Makes copies of itself
c. Cell bursts
2. Lysogenic Infection
a. Virus integrates its DNA into DNA of host cell
b. Viral DNA replicates along with host cell’s DNA
c. Viral DNA embedded in host cell DNA is called - prophage
C.
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Retroviruses
1. Viruses that contain RNA and code for DNA’
2. Responsible for some types of cancer in animals and humans
3. Ex: Acquired Immune Deficiency Syndrome (AIDS)
Figure 19-9 Virus Structures
Section 19-2
Tobacco Mosaic
Virus
T4 Bacteriophage
Head
DNA
Influenza
Virus
RNA
Capsid
proteins
Capsid
RNA
Tail
sheath
Tail
fiber
Surface
proteins
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Membrane
envelope
Figure 19-10 Lytic and Lysogenic Infections
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Figure 19-11 Viruses and Cells
Section 19-2
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Interest Grabber
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.
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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
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
a. Vaccine – weakened or killed pathogens
b. Antibiotics – compounds that block the growth and reproduction
bacteria
B. Controlling Bacteria
1. Sterilization by Heat
2. Disinfectants
3. Food Storage and Processing
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C. Common Bacterial Disease in Humans
1. Lyme Disease
2. Tetanus
3. Tuberculosis
4. Bacterial Meningitis
5. Strep throat
D. Common Viral Disease in Humans
1. Common cold
2. Influenza
3. AIDS
4. Chicken pox
5. Hepatitis B
6. West Nile
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E. Viral Disease in Animals
Ex: Foot-and-mouth disease – cattle, sheep, and pigs
F. Viral Disease in Plants
1. Tobacco Mosaic virus
2. Have difficult time getting into plant cell due to cell wall
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Common Diseases Caused by Bacteria
Section 19-3
Disease
Pathogen
Prevention
Tooth decay
Streptococcus mutans
Regular dental hygiene
Lyme disease
Borrelia burgdorferi
Protection from tick bites
Tetanus
Clostridium tetani
Current tetanus vaccination
Tuberculosis
Mycobacterium tuberculosis
Vaccination
Salmonella food poisoning
Salmonella enteritidis
Proper food-handling practices
Pneumonia
Streptococcus pneumoniae
Maintaining good health
Cholera
Vibrio cholerae
Clean water supplies
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Common Diseases Caused by Viruses
Section 19-3
Type of Virus
Nucleic Acid
Disease
Oncogenic viruses
DNA
Cancer
Retrovirus
RNA
Cancer, AIDS
Adenoviruses
DNA
Respiratory infections
Herpesviruses
DNA
Chickenpox
Poxviruses
DNA
Smallpox
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Video
Lytic and Lysogenic Cycles
Click the image to play the video segment.
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.
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.
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?
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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